3.E: Two-Dimensional Kinematics (Exercises)
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Conceptual Questions
3.2: Vector Addition and Subtraction: Graphical Methods
1. Which of the following is a vector: a person’s height, the altitude on Mt. Everest, the age of the Earth, the boiling point of water, the cost of this book, the Earth’s population, the acceleration of gravity?
2. Give a specific example of a vector, stating its magnitude, units, and direction.
3. What do vectors and scalars have in common? How do they differ?
4. Two campers in a national park hike from their cabin to the same spot on a lake, each taking a different path, as illustrated below. The total distance traveled along Path 1 is 7.5 km, and that along Path 2 is 8.2 km. What is the final displacement of each camper?
5. If an airplane pilot is told to fly 123 km in a straight line to get from San Francisco to Sacramento, explain why he could end up anywhere on the circle shown in Figure. What other information would he need to get to Sacramento?
6. Suppose you take two steps A and B (that is, two nonzero displacements). Under what circumstances can you end up at your starting point? More generally, under what circumstances can two nonzero vectors add to give zero? Is the maximum distance you can end up from the starting point A+B the sum of the lengths of the two steps?
7. Explain why it is not possible to add a scalar to a vector
8. If you take two steps of different sizes, can you end up at your starting point? More generally, can two vectors with different magnitudes ever add to zero? Can three or more?
3.3: Vector Addition and Subtraction: Analytical Methods
9. Suppose you add two vectors A and B . What relative direction between them produces the resultant with the greatest magnitude? What is the maximum magnitude? What relative direction between them produces the resultant with the smallest magnitude? What is the minimum magnitude?
10. Give an example of a nonzero vector that has a component of zero.
11. Explain why a vector cannot have a component greater than its own magnitude.
12. If the vectors A and B are perpendicular, what is the component of A along the direction of B ? What is the component of B along the direction of A ?
3.4: Projectile Motion
13. Answer the following questions for projectile motion on level ground assuming negligible air resistance (the initial angle being neither 0º nor 90º ):
(a) Is the velocity ever zero?
(b) When is the velocity a minimum? A maximum?
(c) Can the velocity ever be the same as the initial velocity at a time other than at \(t=0\)?
(d) Can the speed ever be the same as the initial speed at a time other than at \(t=0\)?
14. Answer the following questions for projectile motion on level ground assuming negligible air resistance (the initial angle being neither \(0º\) nor \(90º\)):
(a) Is the acceleration ever zero?
(b) Is the acceleration ever in the same direction as a component of velocity?
(c) Is the acceleration ever opposite in direction to a component of velocity?
15. For a fixed initial speed, the range of a projectile is determined by the angle at which it is fired. For all but the maximum, there are two angles that give the same range. Considering factors that might affect the ability of an archer to hit a target, such as wind, explain why the smaller angle (closer to the horizontal) is preferable. When would it be necessary for the archer to use the larger angle? Why does the punter in a football game use the higher trajectory?
16. During a lecture demonstration, a professor places two coins on the edge of a table. She then flicks one of the coins horizontally off the table, simultaneously nudging the other over the edge. Describe the subsequent motion of the two coins, in particular discussing whether they hit the floor at the same time.
3.5: Addition of Velocities
17. What frame or frames of reference do you instinctively use when driving a car? When flying in a commercial jet airplane?
18. A basketball player dribbling down the court usually keeps his eyes fixed on the players around him. He is moving fast. Why doesn’t he need to keep his eyes on the ball?
19. If someone is riding in the back of a pickup truck and throws a softball straight backward, is it possible for the ball to fall straight down as viewed by a person standing at the side of the road? Under what condition would this occur? How would the motion of the ball appear to the person who threw it?
20. The hat of a jogger running at constant velocity falls off the back of his head. Draw a sketch showing the path of the hat in the jogger’s frame of reference. Draw its path as viewed by a stationary observer.
21. A clod of dirt falls from the bed of a moving truck. It strikes the ground directly below the end of the truck. What is the direction of its velocity relative to the truck just before it hits? Is this the same as the direction of its velocity relative to ground just before it hits? Explain your answers.
Problems & Exercises
3.2: Vector Addition and Subtraction: Graphical Methods
Use graphical methods to solve these problems. You may assume data taken from graphs is accurate to three digits.
22. Find the following for path A in Figure:
(a) the total distance traveled, and
(b) the magnitude and direction of the displacement from start to finish.
The various lines represent paths taken by different people walking in a city.  Find the following for path B in Figure:
(a) the total distance traveled, and
(b) the magnitude and direction of the displacement from start to finish.
24. Find the north and east components of the displacement for the hikers shown in Figure.
Solution
north component 3.21 km, east component 3.83 km
25.  How far are you from your starting point, and what is the compass direction of a line connecting your starting point to your final position? (If you represent the two legs of the walk as vector displacements A and B , as in Figure, then this problem asks you to find their sum R=A+B .)
The two displacements
A
and
B
add to give a total displacement
R
having magnitude \(R\) and direction \(θ\).
26.
Suppose you first walk 12.0 m in a direction
20º
west of north and then 20.0 m in a direction
40.0º
south of west. How far are you from your starting point, and what is the compass direction of a line connecting your starting point to your final position? (If you represent the two legs of the walk as vector displacements
A
and
B
, as in Figure, then this problem finds their sum
R = A + B
.)
Solution
\(19.5 m, 4.65º\) south of west
27. Repeat the problem above, but reverse the order of the two legs of the walk; show that you get the same final result. That is, you first walk leg B , which is 20.0 m in a direction exactly 40º south of west, and then leg A size 12{A} {}, which is 12.0 m in a direction exactly 20º west of north. (This problem shows that A+B=B+A .)
28. (a) Repeat the problem two problems prior, but for the second leg you walk 20.0 m in a direction 40.0º north of east (which is equivalent to subtracting B from A —that is, to finding R'=A−B ).
(b) Repeat the problem two problems prior, but now you first walk 20.0 m in a direction 40.0º south of west and then 12.0 m in a direction 20.0º east of south (which is equivalent to subtracting A from B —that is, to finding R''=B−A=−R' ). Show that this is the case.
Solution
(a) \(26.6 m, 65.1º\) north of east
(b) \(26.6 m, 65.1º\) south of west
29. Show that the order of addition of three vectors does not affect their sum. Show this property by choosing any three vectors A , B and C , all having different lengths and directions. Find the sum A + B + C then find their sum when added in a different order and show the result is the same. (There are five other orders in which A , B , and C can be added; choose only one.)
30. Show that the sum of the vectors discussed in Example gives the result shown in Figure.
Solution
\(52.9 m, 90.1º\) with respect to the x-axis.
31. Find the magnitudes of velocities \(v_A\) and \(v_B\) in Figure
The two velocities \(v_A\) and \(v_B\) add to give a total \(v_{tot}\).
32. Find the components of \(v_{tot}\) along the x- and y-axes in Figure.
Solution
x-component 4.41 m/s
y-component 5.07 m/s
33. Find the components of \(v_{tot}\) along a set of perpendicular axes rotated \(30º\) counterclockwise relative to those in Figure.
3.3: Vector Addition and Subtraction: Analytical Methods
34. Find the following for path C in Figure:
(a) the total distance traveled and
(b) the magnitude and direction of the displacement from start to finish. In this part of the problem, explicitly show how you follow the steps of the analytical method of vector addition.
The various lines represent paths taken by different people walking in a city. All blocks are 120 m on a side.
Solution
(a) 1.56 km
(b) 120 m east
35. Find the following for path D in Figure:
(a) the total distance traveled and
(b) the magnitude and direction of the displacement from start to finish. In this part of the problem, explicitly show how you follow the steps of the analytical method of vector addition.
36. Find the north and east components of the displacement from San Francisco to Sacramento shown in Figure.
Solution
North-component 87.0 km, east-component 87.0 km
37. Solve the following problem using analytical techniques: Suppose you walk 18.0 m straight west and then 25.0 m straight north. How far are you from your starting point, and what is the compass direction of a line connecting your starting point to your final position? (If you represent the two legs of the walk as vector displacements A and B , as in Figure, then this problem asks you to find their sum R=A+B .)
The two displacements
A
and
B
add to give a total displacement
R
having magnitude \(R\) and direction \(θ\).
Note that you can also solve this graphically. Discuss why the analytical technique for solving this problem is potentially more accurate than the graphical technique.
38. Repeat Exercise using analytical techniques, but reverse the order of the two legs of the walk and show that you get the same final result. (This problem shows that adding them in reverse order gives the same result—that is, B + A = A + B .) Discuss how taking another path to reach the same point might help to overcome an obstacle blocking you other path.
Solution
30.8 m, 35.8 west of north
You drive 7.50 km in a straight line in a direction 15º .
(a) Find the distances you would have to drive straight east and then straight north to arrive at the same point. (This determination is equivalent to find the components of the displacement along the east and north directions.)
(b) Show that you still arrive at the same point if the east and north legs are reversed in order.
39. a) Do Exercise again using analytical techniques and change the second leg of the walk to 25.0 m straight south. (This is equivalent to subtracting B from A —that is, finding R'=A – B )
(b) Repeat again, but now you first walk 25.0 m size 12{"25" "." "0 m"} {} north and then 18.0 m size 12{"18" "." "0 m"} {} east. (This is equivalent to subtract A size 12{A} {} from B size 12{B} {} —that is, to find A=B+C size 12{A=B+C} {}. Is that consistent with your result?)
Solution
(a) \(30.8 m, 54.2º\) south of west
(b) \(30.8 m, 54.2º\) north of east
40. A new landowner has a triangular piece of flat land she wishes to fence. Starting at the west corner, she measures the first side to be 80.0 m long and the next to be 105 m. These sides are represented as displacement vectors A from B in Figure. She then correctly calculates the length and orientation of the third side \(C\). What is her result?
41. You fly 32.0 km size 12{"32" "." "0 km"} {} in a straight line in still air in the direction 35.0º size 12{"35"°} {} south of west.
(a) Find the distances you would have to fly straight south and then straight west to arrive at the same point. (This determination is equivalent to finding the components of the displacement along the south and west directions.)
(b) Find the distances you would have to fly first in a direction 45.0º south of west and then in a direction 45.0º west of north. These are the components of the displacement along a different set of axes—one rotated 45º .
Solution
18.4 km south, then 26.2 km west(b) 31.5 km at
45.0º
south of west, then 5.56 km at
45.0º
west of north
42. A farmer wants to fence off his four-sided plot of flat land. He measures the first three sides, shown as A , B , and C in Figure, and then correctly calculates the length and orientation of the fourth side \(D\). What is his result?
43. In an attempt to escape his island, Gilligan builds a raft and sets to sea. The wind shifts a great deal during the day, and he is blown along the following straight lines: 2.50 km 45.0º north of west; then 4.70 km 60.0º south of east; then 1.30km 25.0º south of west; then 5.10 km straight east; then 1.70km 5.00º east of north; then 7.20 km 55.0º south of west; and finally 2.80 km 10.0º north of east. What is his final position relative to the island?
Solution
\(7.34 km, 63.5º\) south of east
44. Suppose a pilot flies 40.0 km in a direction 60º north of east and then flies 30.0 km in a direction 15º north of east as shown in Figure. Find her total distance \(R\) from the starting point and the direction \(θ\) of the straight-line path to the final position. Discuss qualitatively how this flight would be altered by a wind from the north and how the effect of the wind would depend on both wind speed and the speed of the plane relative to the air mass.
3.4: Projectile Motion
45. A projectile is launched at ground level with an initial speed of 50.0 m/s at an angle of 30.0º above the horizontal. It strikes a target above the ground 3.00 seconds later. What are the \(x\) and \(y\) distances from where the projectile was launched to where it lands?
Solution
\(x=1.30 m×10%2\)
\(y=30.9 m.\)
46. A ball is kicked with an initial velocity of 16 m/s in the horizontal direction and 12 m/s in the vertical direction.
(a) At what speed does the ball hit the ground?
(b) For how long does the ball remain in the air?
(c)What maximum height is attained by the ball?
47. A ball is thrown horizontally from the top of a 60.0-m building and lands 100.0 m from the base of the building. Ignore air resistance.
(a) How long is the ball in the air?
(b) What must have been the initial horizontal component of the velocity?
(c) What is the vertical component of the velocity just before the ball hits the ground? (d) What is the velocity (including both the horizontal and vertical components) of the ball just before it hits the ground?
Solution
(a) 3.50 s
(b) 28.6 m/s
(c) 34.3 m/s
(d) 44.7 m/s,
50.2º
below horizontal
48. (a) A daredevil is attempting to jump his motorcycle over a line of buses parked end to end by driving up a 32º ramp at a speed of 40.0 m/s ( 144 km/h ). How many buses can he clear if the top of the takeoff ramp is at the same height as the bus tops and the buses are 20.0 m long?
(b) Discuss what your answer implies about the margin of error in this act—that is, consider how much greater the range is than the horizontal distance he must travel to miss the end of the last bus. (Neglect air resistance.)
49. An archer shoots an arrow at a 75.0 m distant target; the bull’s-eye of the target is at same height as the release height of the arrow.
(a) At what angle must the arrow be released to hit the bull’s-eye if its initial speed is 35.0 m/s? In this part of the problem, explicitly show how you follow the steps involved in solving projectile motion problems.
(b) There is a large tree halfway between the archer and the target with an overhanging horizontal branch 3.50 m above the release height of the arrow. Will the arrow go over or under the branch?
Solution
(a)
18.4º
(b) The arrow will go over the branch.
50. A rugby player passes the ball 7.00 m across the field, where it is caught at the same height as it left his hand.
(a) At what angle was the ball thrown if its initial speed was 12.0 m/s, assuming that the smaller of the two possible angles was used?
(b) What other angle gives the same range, and why would it not be used?
(c) How long did this pass take?
51 . Verify the ranges for the projectiles in Figure(a) for \(θ=45º\) and the given initial velocities.
Solution
\(R=\frac{v^2_0}{sin2θ_0g}\)
For \(θ=45º,R=\frac{v^2_0}{g}\)
\(R=91.8m\) for \(v_0=30m/s; R=163m\) for \(v_0=40m/s; R=255m\) for \(v_=50m/s\).
52. Verify the ranges shown for the projectiles in Figure(b) for an initial velocity of 50 m/s at the given initial angles.
53. The cannon on a battleship can fire a shell a maximum distance of 32.0 km.
(a) Calculate the initial velocity of the shell.
(b) What maximum height does it reach? (At its highest, the shell is above 60% of the atmosphere—but air resistance is not really negligible as assumed to make this problem easier.)
(c) The ocean is not flat, because the Earth is curved. Assume that the radius of the Earth is \(6.37×10^3km\). How many meters lower will its surface be 32.0 km from the ship along a horizontal line parallel to the surface at the ship? Does your answer imply that error introduced by the assumption of a flat Earth in projectile motion is significant here?
Solution
(a) 560 m/s
(b) \(8.00×10^3m\)
(c) 80.0 m. This error is not significant because it is only 1% of the answer in part (b).
54. An arrow is shot from a height of 1.5 m toward a cliff of height \(H\) size 12{H} {}. It is shot with a velocity of 30 m/s at an angle of 60º above the horizontal. It lands on the top edge of the cliff 4.0 s later.
(a) What is the height of the cliff?
(b) What is the maximum height reached by the arrow along its trajectory?
(c) What is the arrow’s impact speed just before hitting the cliff?
55. In the standing broad jump, one squats and then pushes off with the legs to see how far one can jump. Suppose the extension of the legs from the crouch position is 0.600 m and the acceleration achieved from this position is 1.25 times the acceleration due to gravity, \(g\) size 12{g} {}. How far can they jump? State your assumptions. (Increased range can be achieved by swinging the arms in the direction of the jump.)
Solution
1.50 m, assuming launch angle of
45º
56. The world long jump record is 8.95 m (Mike Powell, USA, 1991). Treated as a projectile, what is the maximum range obtainable by a person if he has a take-off speed of 9.5 m/s? State your assumptions.
57. Serving at a speed of 170 km/h, a tennis player hits the ball at a height of 2.5 m and an angle \(θ\) below the horizontal. The base line is 11.9 m from the net, which is 0.91 m high. What is the angle \(θ\) such that the ball just crosses the net? Will the ball land in the service box, whose service line is 6.40 m from the net?
Solution
\(θ=6.1º\)
yes, the ball lands at 5.3 m from the net
58. A football quarterback is moving straight backward at a speed of 2.00 m/s when he throws a pass to a player 18.0 m straight downfield.
(a) If the ball is thrown at an angle of 25º relative to the ground and is caught at the same height as it is released, what is its initial speed relative to the ground?
(b) How long does it take to get to the receiver?
(c) What is its maximum height above its point of release?
59. Gun sights are adjusted to aim high to compensate for the effect of gravity, effectively making the gun accurate only for a specific range.
(a) If a gun is sighted to hit targets that are at the same height as the gun and 100.0 m away, how low will the bullet hit if aimed directly at a target 150.0 m away? The muzzle velocity of the bullet is 275 m/s.
(b) Discuss qualitatively how a larger muzzle velocity would affect this problem and what would be the effect of air resistance.
Solution
(a) −0.486 m
(b) The larger the muzzle velocity, the smaller the deviation in the vertical direction, because the time of flight would be smaller. Air resistance would have the effect of decreasing the time of flight, therefore increasing the vertical deviation.
60. An eagle is flying horizontally at a speed of 3.00 m/s when the fish in her talons wiggles loose and falls into the lake 5.00 m below. Calculate the velocity of the fish relative to the water when it hits the water.
61. An owl is carrying a mouse to the chicks in its nest. Its position at that time is 4.00 m west and 12.0 m above the center of the 30.0 cm diameter nest. The owl is flying east at 3.50 m/s at an angle 30.0º size 12{"30º} below the horizontal when it accidentally drops the mouse. Is the owl lucky enough to have the mouse hit the nest? To answer this question, calculate the horizontal position of the mouse when it has fallen 12.0 m.
Solution
4.23 m. No, the owl is not lucky; he misses the nest.
62. Suppose a soccer player kicks the ball from a distance 30 m toward the goal. Find the initial speed of the ball if it just passes over the goal, 2.4 m above the ground, given the initial direction to be 40º above the horizontal.
63. Can a goalkeeper at her/ his goal kick a soccer ball into the opponent’s goal without the ball touching the ground? The distance will be about 95 m. A goalkeeper can give the ball a speed of 30 m/s.
Solution
No, the maximum range (neglecting air resistance) is about 92 m.
64. The free throw line in basketball is 4.57 m (15 ft) from the basket, which is 3.05 m (10 ft) above the floor. A player standing on the free throw line throws the ball with an initial speed of 8.15 m/s, releasing it at a height of 2.44 m (8 ft) above the floor. At what angle above the horizontal must the ball be thrown to exactly hit the basket? Note that most players will use a large initial angle rather than a flat shot because it allows for a larger margin of error. Explicitly show how you follow the steps involved in solving projectile motion problems.
65. In 2007, Michael Carter (U.S.) set a world record in the shot put with a throw of 24.77 m. What was the initial speed of the shot if he released it at a height of 2.10 m and threw it at an angle of 38.0º above the horizontal? (Although the maximum distance for a projectile on level ground is achieved at 45º when air resistance is neglected, the actual angle to achieve maximum range is smaller; thus, 38º will give a longer range than 45º in the shot put.)
Solution
15.0 m/s
66. A basketball player is running at 5.00 m/s directly toward the basket when he jumps into the air to dunk the ball. He maintains his horizontal velocity.
(a) What vertical velocity does he need to rise 0.750 m above the floor?
(b) How far from the basket (measured in the horizontal direction) must he start his jump to reach his maximum height at the same time as he reaches the basket?
67. A football player punts the ball at a 45.0º angle. Without an effect from the wind, the ball would travel 60.0 m horizontally.
(a) What is the initial speed of the ball?
(b) When the ball is near its maximum height it experiences a brief gust of wind that reduces its horizontal velocity by 1.50 m/s. What distance does the ball travel horizontally?
Solution
(a) 24.2 m/s
(b) The ball travels a total of 57.4 m with the brief gust of wind.
68. Prove that the trajectory of a projectile is parabolic, having the form \(y=ax+bx^2\). To obtain this expression, solve the equation \(x=v_{0x}t\) for \(t\) and substitute it into the expression for \(y=v_{0y}t–(1/2)gt^2\) (These equations describe the \(x\) and \(y\) positions of a projectile that starts at the origin.) You should obtain an equation of the form \(y=ax+bx^2\) where \(a\) and \(b\) are constants.
69. Derive \(R=\frac{v^2_0sin2θ_0}{g}\) for the range of a projectile on level ground by finding the time \(t\) at which \(y\) becomes zero and substituting this value of \(t\) into the expression for \(x−x_0\), noting that \(R=x−x_0\)
Solution
\(y−y_0=0=v_{0y}t−\frac{1}{2}gt^2=(v_0sinθ)t−\frac{1}{2}gt^2\)
so that \(t=\frac{2(v0sinθ)}{g}\)
\(x−x_0=v_0xt=(v_0cosθ)t=R,\) and substituting for \(t\) gives:
\(R=v_0cosθ(\frac{2v_0sinθ}{g})=\frac{2v^2_0sinθcosθ}{g}\)
since \(2sinθcosθ=sin2θ\), the range is:
\(R=\frac{v_0^2sin2θ}{g}\)
70. Unreasonable Results
(a) Find the maximum range of a super cannon that has a muzzle velocity of 4.0 km/s.
(b) What is unreasonable about the range you found?
(c) Is the premise unreasonable or is the available equation inapplicable? Explain your answer.
(d) If such a muzzle velocity could be obtained, discuss the effects of air resistance, thinning air with altitude, and the curvature of the Earth on the range of the super cannon.
71.  Construct a problem in which you calculate the ball’s needed initial velocity to just clear the fence. Among the things to determine are; the height of the fence, the distance to the fence from the point of release of the ball, and the height at which the ball is released. You should also consider whether it is possible to choose the initial speed for the ball and just calculate the angle at which it is thrown. Also examine the possibility of multiple solutions given the distances and heights you have chosen.
3.5: Addition of Velocities
72. Bryan Allen pedaled a human-powered aircraft across the English Channel from the cliffs of Dover to Cap Gris-Nez on June 12, 1979.
(a) He flew for 169 min at an average velocity of 3.53 m/s in a direction \(45º\) south of east. What was his total displacement?
(b) Allen encountered a headwind averaging 2.00 m/s almost precisely in the opposite direction of his motion relative to the Earth. What was his average velocity relative to the air?
(c) What was his total displacement relative to the air mass?
Solution
(a) \(35.8 km, 45º\) south of east
(b) \(5.53 m/s, 45º\) south of east
(c) \(56.1 km, 45º\) south of east
73. A seagull flies at a velocity of 9.00 m/s straight into the wind.
(a) If it takes the bird 20.0 min to travel 6.00 km relative to the Earth, what is the velocity of the wind?
(b) If the bird turns around and flies with the wind, how long will he take to return 6.00 km?
(c) Discuss how the wind affects the total round-trip time compared to what it would be with no wind.
74. Near the end of a marathon race, the first two runners are separated by a distance of 45.0 m. The front runner has a velocity of 3.50 m/s, and the second a velocity of 4.20 m/s.
(a) What is the velocity of the second runner relative to the first?
(b) If the front runner is 250 m from the finish line, who will win the race, assuming they run at constant velocity?
(c) What distance ahead will the winner be when she crosses the finish line?
Solution
(a) 0.70 m/s faster
(b) Second runner wins
(c) 4.17 m
75. Verify that the coin dropped by the airline passenger in the Example travels 144 m horizontally while falling 1.50 m in the frame of reference of the Earth.
76. A football quarterback is moving straight backward at a speed of 2.00 m/s when he throws a pass to a player 18.0 m straight downfield. The ball is thrown at an angle of \(25.0º\) relative to the ground and is caught at the same height as it is released. What is the initial velocity of the ball relative to the quarterback ?
Solution
\(17.0 m/s, 22.1º\)
77. A ship sets sail from Rotterdam, The Netherlands, heading due north at 7.00 m/s relative to the water. The local ocean current is 1.50 m/s in a direction \(40.0º\) north of east. What is the velocity of the ship relative to the Earth?
78. (a) A jet airplane flying from Darwin, Australia, has an air speed of 260 m/s in a direction \(5.0º\) south of west. It is in the jet stream, which is blowing at 35.0 m/s in a direction \(15º\) south of east. What is the velocity of the airplane relative to the Earth?
(b) Discuss whether your answers are consistent with your expectations for the effect of the wind on the plane’s path.
Solution
(a) \(230 m/s, 8.0º\) south of west
(b) The wind should make the plane travel slower and more to the south, which is what was calculated.
79. (a) In what direction would the ship in Exercise have to travel in order to have a velocity straight north relative to the Earth, assuming its speed relative to the water remains \(7.00 m/s\)?
(b) What would its speed be relative to the Earth?
80. (a) Another airplane is flying in a jet stream that is blowing at 45.0 m/s in a direction 20º size 12{"20º"} {} south of east (as in Exercise). Its direction of motion relative to the Earth is 45.0º size 12{"45.0º"} {} south of west, while its direction of travel relative to the air is 5.00º size 12{5.00º} {} south of west. What is the airplane’s speed relative to the air mass? (b) What is the airplane’s speed relative to the Earth?
Solution
(a) 63.5 m/s
(b) 29.6 m/s
81. A sandal is dropped from the top of a 15.0-m-high mast on a ship moving at 1.75 m/s due south. Calculate the velocity of the sandal when it hits the deck of the ship:
(a) relative to the ship and
(b) relative to a stationary observer on shore.
(c) Discuss how the answers give a consistent result for the position at which the sandal hits the deck.
82. The velocity of the wind relative to the water is crucial to sailboats. Suppose a sailboat is in an ocean current that has a velocity of 2.20 m/s in a direction \(30.0º\) east of north relative to the Earth. It encounters a wind that has a velocity of 4.50 m/s in a direction of \(50.0º\) south of west relative to the Earth. What is the velocity of the wind relative to the water?
Solution
\(6.68 m/s, 53.3º\) south of west
83. The great astronomer Edwin Hubble discovered that all distant galaxies are receding from our Milky Way Galaxy with velocities proportional to their distances. It appears to an observer on the Earth that we are at the center of an expanding universe. Figure illustrates this for five galaxies lying along a straight line, with the Milky Way Galaxy at the center. Using the data from the figure, calculate the velocities:
(a) relative to galaxy 2 and
(b) relative to galaxy 5.
The results mean that observers on all galaxies will see themselves at the center of the expanding universe, and they would likely be aware of relative velocities, concluding that it is not possible to locate the center of expansion with the given information.
Five galaxies on a straight line, showing their distances and velocities relative to the Milky Way (MW) Galaxy. The distances are in millions of light years (Mly), where a light year is the distance light travels in one year. The velocities are nearly proportional to the distances. The sizes of the galaxies are greatly exaggerated; an average galaxy is about 0.1 Mly across.
84. (a) Use the distance and velocity data in Figure to find the rate of expansion as a function of distance.
(b) If you extrapolate back in time, how long ago would all of the galaxies have been at approximately the same position? The two parts of this problem give you some idea of how the Hubble constant for universal expansion and the time back to the Big Bang are determined, respectively.
Solution
(a) \(H_{average}=14.9\frac{km/s}{Mly}\)
(b) 20.2 billion years
85. An athlete crosses a 25-m-wide river by swimming perpendicular to the water current at a speed of 0.5 m/s relative to the water. He reaches the opposite side at a distance 40 m downstream from his starting point. How fast is the water in the river flowing with respect to the ground? What is the speed of the swimmer with respect to a friend at rest on the ground?
86. A ship sailing in the Gulf Stream is heading \(25.0º\) west of north at a speed of 4.00 m/s relative to the water. Its velocity relative to the Earth is \(4.80 m/s 5.00º\) west of north. What is the velocity of the Gulf Stream? (The velocity obtained is typical for the Gulf Stream a few hundred kilometers off the east coast of the United States.)
Solution
\(1.72 m/s, 42.3º\)north of east
87. An ice hockey player is moving at 8.00 m/s when he hits the puck toward the goal. The speed of the puck relative to the player is 29.0 m/s. The line between the center of the goal and the player makes a \(90.0º\) angle relative to his path as shown in Figure. What angle must the puck’s velocity make relative to the player (in his frame of reference) to hit the center of the goal?
An ice hockey player moving across the rink must shoot backward to give the puck a velocity toward the goal.
88. Unreasonable Results
Suppose you wish to shoot supplies straight up to astronauts in an orbit 36,000 km above the surface of the Earth.
(a) At what velocity must the supplies be launched?
(b) What is unreasonable about this velocity?
(c) Is there a problem with the relative velocity between the supplies and the astronauts when the supplies reach their maximum height?
(d) Is the premise unreasonable or is the available equation inapplicable? Explain your answer.
89. Unreasonable Results
A commercial airplane has an air speed of \(280 m/s\) due east and flies with a strong tailwind. It travels 3000 km in a direction \(5º\) south of east in 1.50 h.
(a) What was the velocity of the plane relative to the ground?
(b) Calculate the magnitude and direction of the tailwind’s velocity.
(c) What is unreasonable about both of these velocities?
(d) Which premise is unreasonable?
90.  Construct a problem in which you calculate the angle the airplane must fly relative to the air mass in order to have a velocity parallel to the runway. Among the things to consider are the direction of the runway, the wind speed and direction (its velocity) and the speed of the plane relative to the air mass. Also calculate the speed of the airplane relative to the ground. Discuss any last minute maneuvers the pilot might have to perform in order for the plane to land with its wheels pointing straight down the runway.
Contributors and Attributions
-
Paul Peter Urone (Professor Emeritus at California State University, Sacramento) and Roger Hinrichs (State University of New York, College at Oswego) with Contributing Authors: Kim Dirks (University of Auckland) and Manjula Sharma (University of Sydney). This work is licensed by OpenStax University Physics under a Creative Commons Attribution License (by 4.0) .


5.4: Active Transport
By the end of this section, you will be able to do the following:
- Understand how electrochemical gradients affect ions
- Describe endocytosis, including phagocytosis, pinocytosis, and receptor-mediated endocytosis
- Understand the process of exocytosis
Active transport mechanisms require the use of the cell’s energy, usually in the form of adenosine triphosphate (ATP). If a substance must move into the cell against its concentration gradient, that is, if the concentration of the substance inside the cell must be greater than its concentration in the extracellular fluid, the cell must use energy to move the substance. Some active transport mechanisms move small-molecular weight material, such as ions, through the membrane.
In addition to moving small ions and molecules through the membrane, cells also need to remove and take in larger molecules and particles. Some cells are even capable of engulfing entire unicellular microorganisms. You might have correctly hypothesized that the uptake and release of large particles by the cell requires energy. A large particle, however, cannot pass through the membrane, even with energy supplied by the cell.
Electrochemical Gradient
We have discussed simple concentration gradients—differential concentrations of a substance across a space or a membrane—but in living systems, gradients are more complex. Because cells contain proteins, most of which are negatively charged, and because ions move into and out of cells, there is an electrical gradient, a difference of charge, across the plasma membrane. The interior of living cells is electrically negative with respect to the extracellular fluid in which they are bathed; at the same time, cells have higher concentrations of potassium (K + ) and lower concentrations of sodium (Na + ) than does the extracellular fluid. Thus, in a living cell, the concentration gradient and electrical gradient of Na + promotes diffusion of the ion into the cell, and the electrical gradient of Na + (a positive ion) tends to drive it inward to the negatively charged interior. The situation is more complex, however, for other elements such as potassium. The electrical gradient of K + promotes diffusion of the ion into the cell, but the concentration gradient of K + promotes diffusion out of the cell (Figure \(\PageIndex{1}\)). The combined gradient that affects an ion is called its electrochemical gradient, and it is especially important to muscle and nerve cells.
Moving Against a Gradient
To move substances against a concentration or an electrochemical gradient, the cell must use energy. This energy is harvested from ATP that is generated through cellular metabolism. Active transport mechanisms, collectively called pumps or carrier proteins, work against electrochemical gradients. With the exception of ions, small substances constantly pass through plasma membranes. Active transport maintains concentrations of ions and other substances needed by living cells in the face of these passive changes. Much of a cell’s supply of metabolic energy may be spent maintaining these processes. Because active transport mechanisms depend on cellular metabolism for energy, they are sensitive to many metabolic poisons that interfere with the supply of ATP.
Two mechanisms exist for the transport of small-molecular weight material and macromolecules. Primary active transport moves ions across a membrane and creates a difference in charge across that membrane. The primary active transport system uses ATP to move a substance, such as an ion, into the cell, and often at the same time, a second substance is moved out of the cell. The sodium-potassium pump, an important pump in animal cells, expends energy to move potassium ions into the cell and a different number of sodium ions out of the cell (Figure \(\PageIndex{2}\)). The action of this pump results in a concentration and charge difference across the membrane.
Secondary active transport describes the movement of material using the energy of the electrochemical gradient established by primary active transport. Using the energy of the electrochemical gradient created by the primary active transport system, other substances such as amino acids and glucose can be brought into the cell through membrane channels. ATP itself is formed through secondary active transport using a hydrogen ion gradient in the mitochondrion.
Endocytosis
Endocytosis is a type of active transport that moves particles, such as large molecules, parts of cells, and even whole cells, into a cell. There are different variations of endocytosis, but all share a common characteristic: The plasma membrane of the cell invaginates, forming a pocket around the target particle. The pocket pinches off, resulting in the particle being contained in a newly created vacuole that is formed from the plasma membrane.
Phagocytosis is the process by which large particles, such as cells, are taken in by a cell. For example, when microorganisms invade the human body, a type of white blood cell called a neutrophil removes the invader through this process, surrounding and engulfing the microorganism, which is then destroyed by the neutrophil (Figure \(\PageIndex{3}\)).
A variation of endocytosis is called pinocytosis. This literally means “cell drinking” and was named at a time when the assumption was that the cell was purposefully taking in extracellular fluid. In reality, this process takes in solutes that the cell needs from the extracellular fluid (Figure \(\PageIndex{3}\)).
A targeted variation of endocytosis employs binding proteins in the plasma membrane that are specific for certain substances (Figure \(\PageIndex{3}\)). The particles bind to the proteins and the plasma membrane invaginates, bringing the substance and the proteins into the cell. If passage across the membrane of the target of receptor-mediated endocytosis is ineffective, it will not be removed from the tissue fluids or blood. Instead, it will stay in those fluids and increase in concentration. Some human diseases are caused by a failure of receptor-mediated endocytosis. For example, the form of cholesterol termed low-density lipoprotein or LDL (also referred to as “bad” cholesterol) is removed from the blood by receptor-mediated endocytosis. In the human genetic disease familial hypercholesterolemia, the LDL receptors are defective or missing entirely. People with this condition have life-threatening levels of cholesterol in their blood, because their cells cannot clear the chemical from their blood.
Exocytosis
In contrast to these methods of moving material into a cell is the process of exocytosis. Exocytosis is the opposite of the processes discussed above in that its purpose is to expel material from the cell into the extracellular fluid. A particle enveloped in membrane fuses with the interior of the plasma membrane. This fusion opens the membranous envelope to the exterior of the cell, and the particle is expelled into the extracellular space (Figure \(\PageIndex{4}\)).
Contributors and Attributions
Remixed and/or curated from the following works:
Fowler, S., Roush, R., & Wise, J. (2013). 3.6 Active Transport . In Concepts of Biology . OpenStax (CC BY 4.0; Access for free at https://openstax.org/books/concepts-biology/pages/1-introduction ).


7.5: Inertia and Rates of Change
Learning Objectives
- How to get around a curvilinear coordinate system
Suppose that we describe a ﬂying bullet in polar coordinates. We neglect the vertical dimension, so the bullet’s motion is linear. If the bullet has a displacement of \((∆r_1,∆θ_1)\) in an short time interval \(∆t\), then clearly at a later point in its motion, during an equal interval, it will have a displacement \((∆r_2,∆θ_2)\) with two different numbers inside the parentheses. This isn’t because its velocity or momentum really changed. It’s because the coordinate system is curvilinear. There are three ways to get around this:
- Use only Minkowski coordinates.
- Instead of characterizing inertial motion as motion with constant velocity components, we can instead characterize it as motion that maximizes the proper time ( section 2.4).
- Define a correction term to be added when taking the derivative of a vector or covector expressed in non-Minkowski coordinates.
These issues become more acute in general relativity, where curvature of spacetime can make option 1 impossible. Option 3, called the covariant derivative, is discussed in optional section 9.4. If you aren’t going to read that section, just keep in mind that in non-Minkowski coordinates, you cannot naively use changes in the components of a vector as a measure of a change in the vector itself.


5.2: Period and Frequency in Oscillations
Learning Objectives
- Understand the relationship between the frequency and the period of oscillations.
- Determine the frequency of oscillations.
When you pluck a guitar string, the resulting sound has a steady tone and lasts a long time. Each successive vibration of the string takes the same time as the previous one. We define periodic motion to be a motion that repeats itself at regular time intervals, such as exhibited by the guitar string or by an object on a spring moving up and down. The time to complete one oscillation remains constant and is called the period \(T\) . Its units are usually seconds, but may be any convenient unit of time. The word period refers to the time for some event whether repetitive or not; but we shall be primarily interested in periodic motion, which is by definition repetitive. A concept closely related to period is the frequency of an event. For example, if you get a paycheck twice a month, the frequency of payment is two per month and the period between checks is half a month. Frequency \(f\) is defined to be the number of events per unit time. For periodic motion, frequency is the number of oscillations per unit time. The relationship between frequency and period is
\[f=\frac{1}{T}. \nonumber \]
The SI unit for frequency is the cycle per second , which is defined to be a hertz (Hz):
\[1 \mathrm{~Hz}=1 \frac{\text { cycle }}{\mathrm{sec}} \text { or } 1 \mathrm{~Hz}=\frac{1}{\mathrm{~s}} \nonumber \]
A cycle is one complete oscillation. Note that a vibration can be a single or multiple event, whereas oscillations are usually repetitive for a significant number of cycles.
Example \(\PageIndex{1}\): Determine the Frequency of Two Oscillations: Medical Ultrasound and the Period of Middle C
We can use the formulas presented in this module to determine both the frequency based on known oscillations and the oscillation based on a known frequency. Let’s try one example of each. (a) A medical imaging device produces ultrasound by oscillating with a period of 0.400 µs. What is the frequency of this oscillation? (b) The frequency of middle C on a typical musical instrument is 264 Hz. What is the time for one complete oscillation?
Strategy
Both questions (a) and (b) can be answered using the relationship between period and frequency. In question (a), the period \(T\) is given and we are asked to find frequency \(f\). In question (b), the frequency \(f\) is given and we are asked to find the period \(T\) .
Solution a
-
Substitute 0.400 \( \mu \mathrm{s}\) for \(T\) in \(f=\frac{1}{T}\):
\[f=\frac{1}{T}=\frac{1}{0.400 \times 10^{-6} \mathrm{~s}}. \nonumber\]
Solve to find
\[f=2.50 \times 10^{6} \mathrm{~Hz}. \nonumber\]
Discussion a
The frequency of sound found in (a) is much higher than the highest frequency that humans can hear and, therefore, is called ultrasound. Appropriate oscillations at this frequency generate ultrasound used for noninvasive medical diagnoses, such as observations of a fetus in the womb.
Solution b
-
Identify the known values:
The time for one complete oscillation is the period \(T\) :
\[f=\frac{1}{T}. \nonumber\]
-
Solve for
\(T\)
:
\[T=\frac{1}{f}. \nonumber\]
-
Substitute the given value for the frequency into the resulting expression:
\[T=\frac{1}{f}=\frac{1}{264 \mathrm{~Hz}}=\frac{1}{264 \mathrm{cycles} / \mathrm{s}}=3.79 \times 10^{-3} \mathrm{~s}=3.79 \mathrm{~ms}. \nonumber\]
Discussion
The period found in (b) is the time per cycle, but this value is often quoted as simply the time in convenient units (ms or milliseconds in this case).
Exercise \(\PageIndex{1}\)
Identify an event in your life (such as receiving a paycheck) that occurs regularly. Identify both the period and frequency of this event.
- Answer
-
I visit my parents for dinner every other Sunday. The frequency of my visits is 26 per calendar year. The period is two weeks.
Section Summary
- Periodic motion is a repetitious oscillation.
- The time for one oscillation is the period \(T\).
- The number of oscillations per unit time is the frequency \(f\) .
-
These quantities are related by
\[f=\frac{1}{T}. \nonumber\]
Glossary
- period
- time it takes to complete one oscillation
- periodic motion
- motion that repeats itself at regular time intervals
- frequency
- number of events per unit of time


1.9: Jurassic Park- World of Reptiles
The climate on Earth in this epoch (Jurassic and Early Cretaceous) approached the optimum, the split of the continental plates led to its humidification. A new flourishing of fauna and flora began. The sea strongly prevailed over the land, even high continental platforms such as the Russian and North African, were flooded.
The abundance of phytoplankton and zooplankton caused the thrive of marine fauna, including sponges, corals, bivalve mollusks (who took an active part in the construction of bioherms), echinoderms, etc. Ichthyosaurs and plesiosaurs were the most abundant marine predators.
Interestingly that in fossil deposits, pregnant females of ichthyosaurs are often found. Therefore, the ichthyosaurs were not only viviparous but also gave birth in conditions that “promoted” fossilization. The reason is they likely could not give birth as modern cetaceans: a tail up, this was not allowed with their vertical (like in fish, but not like in cetaceans) caudal fin. Then it seems that they were forced to give birth in shallow water, probably forming large groups (like modern seals).
On land, there were forests similar to the recent temperate taiga, composed mainly of representatives of the ginkgo class. Many of them were technically also angiosperms as their seeds were well protected by additional covers. These forests were mostly inhabited by insects, and primitive mammals hunted for them.
In open spaces, savanna forests were maintained (as modern grasslands exist only due to the constant pressure of ungulates) by giant herbivorous dinosaurs, replacing all the other groups with size of a modern cow and bigger. There also lived numerous predatory dinosaurs, both large and small bird-like insectivorous forms.
Flight of ancient birds was still very imperfect. The ancestors of birds needed feathers mainly for thermal insulation, and the flight occurred from the jumping movements required to catch flying insects. There is no much difference between archosauromorph reptiles and birds; in fact, flying is the only radical difference of birds.
The other group of flying archosaurs, pterosaurs, dominated the water and land borders. Ancestors of pterosaurs were fish-eating animals, and their flight arose as an adaptation to catching prey from the water.


14.1.2: Longshore Transport
We learned previously that refraction causes waves to approach parallel to shore. However, most waves still reach the shore at a small angle, and as each one arrives, it pushes water along the shore, creating what is known as a longshore current within the surf zone (the areas where waves are breaking) (Figure \(\PageIndex{1}\)). Longshore currents can move up to 4 km/hr, strong enough to carry people with them, as everyone knows who has been swimming in the ocean only to look up and see that they have been carried far down the beach from their towel!
Another important effect of waves reaching the shore at an angle is that when they wash up onto the beach, they do so at an angle, but when that same wave water washes back down the beach, it moves straight down the slope of the beach (Figure \(\PageIndex{2}\)). The upward-moving water, known as the swash, pushes sediment particles along the beach, while the downward-moving water, the backwash, brings them straight back. With every wave that washes up and then down the beach, particles of sediment are moved along the beach in a zigzag pattern.
The combined effects of sediment transport within the surf zone by the longshore current and sediment movement along the beach by swash and backwash is known as longshore transport , or littoral drift . Longshore transport moves a tremendous amount of sediment along coasts (both oceans and large lakes) around the world, and it is responsible for creating a variety of depositional features. The net movement of sediment due to longshore transport is to the south along both coasts of the continental United States, because the storms and high winds that originally create the swell tend to occur at higher latitudes and move to the south.
A rip current (often incorrectly called a “rip tide”; they are not really related to tides) is another type of current that develops in the nearshore area, and has the effect of returning water that has been pushed up to the shore by incoming waves or accumulated through longshore currents, particularly converging longshore currents. Rip currents often occur where there is a channel between sandbars that makes it easier for the retreating water to escape. As shown in Figure \(\PageIndex{3}\), rip currents flow straight out from the shore, and because the water is directed through a narrow space, the current can be very strong. The currents lose strength quickly just outside of the surf zone, but they can be dangerous to swimmers who get caught in them and are pulled away from shore. Swimmers caught in a rip current should not try to swim directly back to shore, as it is difficult to fight the current and the swimmer can quickly tire. Instead, swim parallel to the beach for a short distance until you are outside of the rip current, and then you can easily swim to shore.
Rip currents are visible in Figure \(\PageIndex{4}\), a beach at Tunquen in Chile near Valparaiso. As is evident from the photo, the rips correspond with embayments in the beach profile. Three of them are indicated with arrows, but it appears that there may be several others farther along the beach.
*”Physical Geology” by Steven Earle used under a CC-BY 4.0 international license. Download this book for free at http://open.bccampus.ca


6.15: Reading- Using Marketing Information
Translating Marketing Information into Action
With marketing information and research results collected, it’s now the responsibility of marketers to share this information internally with people who need to understand it. It’s standard practice to hold meetings with appropriate team members to walk through the research findings and brainstorm together about how to apply the results to marketing strategy and operations. It’s also good practice to make the research report available on a company intranet or other central forum, where people who need the information can readily find and access it.
The reception to research results may vary from person to person or from team to team. In some cases, where marketers have been waiting on the research results before they move forward, the new information fills a gap in their knowledge. They are likely very eager to take guidance from the research and charge ahead. In other cases, marketers may have a vested interest in continuing to do the things they’ve always done—perhaps because they dislike change or because they think the original course of action is still working. In these situations, if the research suggests that a course change is necessary, there may be significant resistance.
Start Conversations About New Customer Insights
To help encourage a better reception to what the organization is learning from marketing information, it may be useful to review the original problem the research is trying to solve. Remind team members that the goal of using marketing information is to gain new customer insights that will help make the organization more effective. With this in mind, marketers should think about how the research results can help them better understand customers and translate this understanding into adjustments to the marketing mix to better address customers’ needs. By framing research results around a deeper or broader understanding of the customer, it can help defuse resistance and make people feel more informed and empowered to make good marketing decisions.
The following section lists the types of questions marketers can explore as they brainstorm about how marketing information and research results can help them adjust marketing strategy and improve the marketing mix. These questions are a useful jumping-off point for deeper conversations about new customer insights and how to put them into action.
Using Marketing Information to Shape Marketing Strategy: Types of Questions to Explore
Target Segment(s)
- What new insights do we have about our target segment(s)?
- Which problems should we be solving for our customers?
- Are we targeting the right segments?
Product
- What attracts customers to our products?
- What improvements would make them even more attractive to our target segments?
Promotion
- What types of messages will make target segments want our products?
- What types of promotional campaigns will work best for each target segment?
- Who do out target segments listen to, and what are they saying about us?
Price
- How are we going at providing good value for the price?
- How does out pricing affect customers’ willingness to buy?
- How would changes to pricing affect sales?
Place
- Are we offering our products in the places and times that target segments feel the need for them? If now, how can we improve?
- How can we make it easier for customers to find and buy our products?
- Are there more efficient ways for us to get out products into customers’ hands?
Don’t Forget to Measure Impact
As marketers begin to apply the research findings and recommendations, it is essential to track the impact of the new strategy to determine whether the original problem or challenge is being addressed. If the original marketing problem was focused on improving the messaging associated with a product, for example, then the organization should start to see improved lead generation, inquiries, and/or sales once the new messaging is adopted and implemented. If the original marketing problem was focused on which segments to target and how to reach them, organizations should be able to track improvements in interest and sales among these segments after they have begun to implement a market mix focused on these segments.
This link between taking action and measuring results is important. It provides a continuing stream of marketing information to help marketers understand if they are on the right path and where to continue to make adjustments. Eventually this process will surface new marketing problems that warrant attention through the marketing research process. In this way, the process of using marketing information to solve problems becomes a continuous cycle.
What does this process look like in the real world? Let’s examine two examples.
For decades, the consumer products company Procter & Gamble has been a visible leader when it comes to relying on marketing research and using it to guide marketing strategy decisions. In particular, it has focused on ways of entering new markets and establishing a leading market position. As it explored opportunities for market leadership in China, one standout product category was disposable diapers, a profitable category for P&G in the U.S. and other global markets.
In the early 2000s, the company rushed in to launch Pampers in China, its leading disposable diaper brand. The effort flopped. Culturally, Chinese parents did not see the need for the new American disposable diaper product. They were doing fine using cloth diapers and kaidangku , the open-crotch pants used traditionally for infants and young children. Instead of pulling out, P&G turned to marketing research for additional insights about ways of generating demand for Pampers. The research focused on identifying “winning qualities” of disposable diapers that would make Chinese mothers interested in trying the product. It concluded that improving infants’ sleep quality could become a powerful motivator.
In 2007, P&G launched campaign called “Golden Sleep” to promote the idea that Pampers disposable diapers can help babies fall asleep faster and sleep with less disruption. Marketing research was directly responsible P&G’s adjustments to product positioning and promotion strategy. The campaign invited parents to upload pictures of their sleeping babies to a Chinese Pampers Web site. This reinforced the link between Pampers products and the message of “better sleep for babies.” The ad campaign also featured research results linked to Pampers and infant sleep such as, “Baby Sleeps with 50 percent Less Disruption,” and “Baby Falls Asleep 30 percent Faster.”
“Golden Sleep” was a tremendous success, moving Pampers to a leading market position and creating broad demand for a product category that was previously almost nonexistent in China. P&G attribute this success to the insights generated by a marketing team and research effort focused on better understanding and addressing customer needs. [1]
A fast-food restaurant chain identified milkshakes as a focus for improving sales. Initial marketing research efforts were focused on creating a “typical” milkshake-drinker profile. The researchers then found people who fit the profile and were willing to help them understand what constituted the ideal milkshake: thick or thin? Which flavors? Smooth or chunky? These effort led the company to tinker with its milkshake products, segmentation, targeting, and promotion strategies, but sales still did not improve.
The company hired an outside researcher to help the company understand what they might be missing about milkshakes. This researcher spent time in a restaurant observing and documenting milkshake sales, as well as talking to milkshake buyers about why they had made their product choice. A couple of key insights emerged about milkshake buyers. First and somewhat surprising, 40 percent of milkshake sales took place early in the morning, and the buyers were commuters on their way to work. Second, the ideal milkshake for these customers was thick and substantial but easy to consume during a commute. Third, another key buyer audience was parents purchasing a treat for children, but the ideal milkshake for them was a thinner product children can drink quickly with a straw.
Acting on these new insights, the company adjusted its marketing strategy. Instead of focusing on a single “milkshake buyer” profile, it reformulated its milkshake products and promotion strategy to better fit the needs of different types of target milkshake customers. It offered a thicker, chunkier “morning milkshake” to appeal to commuters who wanted a satisfying alternative to a morning donut or bagel. The chain also introduced a different milkshake positioned as a kid treat, which offered the thinner, easier-and-quicker-to drink benefits parents wanted. Persistence and perseverance in the marketing research process led the company to dig deeper to understand customers, their unique needs, and how to adjust marketing strategy in response to this new information. [2]
Contributors and Attributions
- Reading: Using Marketing Information. Authored by : Lumen Learning. License : CC BY: Attribution
- Cake Milkshake Heaven. Authored by : Tina H. Located at : www.flickr.com/photos/ohocheese/4963121362/. License : CC BY-NC-ND: Attribution-NonCommercial-NoDerivatives
- Image: Feedback . Authored by : Tumisu. Provided by : Pixabay. Located at : pixabay.com/illustrations/feedback-group-communication-2044700/. License : CC0: No Rights Reserved . License Terms : Pixabay License


4.3: Exercise and the Brain
Overview
For centuries, researchers have sought to elucidate the mechanisms behind the axiom that a healthy body leads to a healthy mind. It has now been established that exercise, even among minimal commitment exercise routines, has an array of robust effects on the brain, such as enhanced memory, mood, cognitive functioning, plasticity, and learning capabilities ( Erickson et al., 2011 ; Spalding et al., 2013 ; Phillips et al., 2014 ). Most notably, exercise has been implicated in having anti-depressant effects and counteracting disease or age-related mental impairment and atrophy, such as Alzheimer’s disease or dementia ( Laurin et al., 2001 ). Yet, until recently, the intermediaries between exercise and its health benefits have not been well-understood.
However, it has been shown that—contrary to the age-old notion that the number of neurons in the brain remains static after prenatal and neonatal development—new neurons can be generated in the adult brain via a process known as neurogenesis, which can attenuate the deleterious effects of neurodegeneration ( van Praag et al., 1999 ). This phenomenon has been linked to exercise, with a significant portion of subsequent neural growth occurring in the dentate gyrus of the hippocampus ( Cotman and Berchtold, 2002 ). Since the hippocampus is critical for memory consolidation and learning, the generation of new neurons and increased plasticity in this brain region may explain the improved cognition and emotional state that accompanies exercise ( Gandy et al., 2017 ; Trinchero et al., 2017 ). Furthermore, preliminary research has suggested that neurogenesis may also occur in numerous other areas of the brain, including the amygdala and hypothalamus, which may explain the diversity of exercise-derived benefits ( Fowler et al., 2008 ). However, this research is not as extensive or conclusive as hippocampal neurogenesis research, nor is the extent to which neurogenesis occurs in other brain regions as robust as it is in the hippocampus, with the exception of the olfactory bulb ( Cotman et al., 2007 ). One key molecule, brain-derived neurotrophic factor (BDNF), has been shown to modulate neurogenesis and exercise likely influences BDNF levels to alter areas of the brain.
Exercise and Hippocampal Neurogenesis
In rodents, hippocampal neurogenesis as a function of exercise has been extensively demonstrated and replicated. To test this, rodents are injected with bromodeoxyuridine (BrdU), which signify actively mitotic cells and are incorporated by daughter cells, thereby allowing the tracing of cell division ( del Rio and Soriano, 1989 ). In some of the earliest work in this field, it was shown that mice allowed to voluntarily exercise on a running wheel exhibited enhanced neurogenesis in the dentate gyrus. By utilizing BrdU as a tracing molecule, it was observed that exercise not only increased proliferation of the progenitor cells in the subgranular zone, but also increased their survival rate as they differentiated and matured ( van Praag et al., 1999 ; Seri et al., 2001 ; for reviews of neural progenitors and lineage progression see Weissman et al., 2001 ; Seri et al., 2004 ; Göritz and Frisén, 2012 ).
Although it is much more difficult to study exercise-mediated neurogenesis in humans, there is significant evidence that neurogenesis occurs in the adult human brain, especially in the dentate gyrus. Indeed, exercise has been shown to increase the size of the hippocampus in human adults ( Erickson et al., 2011 ). Through postmortem tissue analysis of cancer patients administered BrdU, it has been shown that mature granule neurons are continually generated from the subgranular zone, even in the later stages of life ( Eriksson et al., 1998 ). Interestingly, the participants in this study were not assigned to exercise conditions, and since they were cancer patients near death, it is unlikely they participated in any exercise regimen. This suggests that the hippocampus has the capability to generate new neurons in adulthood independent of exercise. Later sections in this review, however, provide evidence that exercise accentuates neurogenesis in humans and addresses how the amount of exercise modulates the degree of neurogenesis.
BDNF Mediation of Hippocampal Neurogenesis
Given these early findings establishing a connection between exercise and hippocampal neurogenesis, researchers next turned to examining the biological underpinnings. One of the strongest candidates for bridging the gap between exercise and neurogenesis is BDNF, a growth factor categorized under the neurotrophin family widely expressed in the brain and throughout the rest of the central nervous system ( Salehi et al., 2003 ). Early research on this molecule found that during development in mice, BDNF expression is low during prenatal development, but then increases during the first few weeks after being born and peaks during the shift from embryonic to adult neurogenesis ( Bath et al., 2012 ). This provides key insight into its potential for facilitating neurogenesis, which then spurred much more research interest in its connection to neurogenesis.
BDNF
As a whole, the neurotrophin family polypeptides are vital to the regulation of the neural processes in neurogenesis, such as proliferation, differentiation, maturation, and plasticity. Within this family, BDNF exhibits the highest degree of expression in the brain, and is primarily synthesized there during exercise ( Reichardt, 2006 ). BDNF can also enter the brain via freely diffusing across the blood brain barrier ( Pan et al., 1998 ; Mousavi and Jasmin, 2006 ). Furthermore, during exercise, proteins and their metabolic derivatives secreted from peripheral muscles, such as cathepsin B and FNDC5/irisin, also cross the blood brain barrier to mediate BDNF expression in the hippocampus and subsequent neurogenesis and memory improvement ( Wrann et al., 2013 ; Moon et al., 2016 ). Indeed, mice injected with skeletal muscle endurance factors had elevated levels of hippocampal neurogenesis and increased spatial memory ( Kobilo et al., 2010 ).
BDNF functions by binding to tropomyosin receptor kinase B (TrkB), which is largely expressed in hippocampal neurons. Upon binding, the BDNF-TrkB complex serves as a docking site for numerous signaling cascades, protein phosphorylation cascades, and secondary signaling systems ( Huang and Reichardt, 2003 ; Nykjaer et al., 2005 ; Yoshii and Constantine-Paton, 2010 ). Through these pathways (shown in Figure \(\PageIndex{1}\)), BDNF can exert significant regulatory control over many facets of a neuron’s function and thereby influence how these neurons function as a whole within the hippocampus.
Figure \(\PageIndex{1}\).
Pathways that BDNF activates. Brain-derived neurotrophic factor activates TrkB through several downstream signaling pathways, such as AKT, CaMK, Ras/Raf/MEK/ERK leading to cell survival, growth, and neuroplasticity. BDNF activates TrkB stimulation via phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) and also activates proteins like Shc, Grb-2, and Gab-1. The PI3K is also activated by binding to Ras homolog enriched by brain glutamine triphosphate (Ras-GTP). Image from:
https://doi.org/10.3389/fneur.2016.00094
. Under CC by 4.0
Exercise and BDNF Expression
Thus far, both exercise and BDNF have been shown to be associated with increased neurogenesis. Further research has extended this to show that treadmill exercise in mice and aerobic exercise in humans increases BDNF expression by regulating BDNF gene expression in the hippocampus ( Kim et al., 2015 ). This process is largely mediated by neurotransmitter and neuroendocrine systems, with extensive literature supporting acetylcholine (ACh) as a key regulator ( Knipper et al., 1994 ).
In mice allowed to voluntarily engage in wheel running, an increase in BDNF mRNA levels in the dentate gyrus was observed after only a few days of exercise ( Neeper et al., 1995 ). Surprisingly, these levels were maintained throughout several weeks of exercise and corresponded to proportional increases in BDNF protein expression ( Russo-Neustadt et al., 1999 ). When the exercise conditions were supplemented with antibodies blocking TrkB, however, the mice had attenuated learning capabilities involving the hippocampus. Furthermore, these mice also lacked synaptic-specific proteins in the hippocampus, thereby demonstrating that BDNF signaling is necessary to allow the benefits of exercise to manifest ( Vaynman et al., 2004 , 2006 ).
Research has also shown that metrics of overall health quality in humans follow a dose-dependent relationship with the duration and intensity of exercise, with the best outcomes linked to moderate exercise ( Larson et al., 2006 ). Further work illustrates that mice show greater improvements in acquisition and retention based learning in hippocampus-dependent tasks following long-term exercise rather than shorter regimes of exercise ( Handschin and Spiegelman, 2008 ; Parachikova et al., 2008 ; Ploeger et al., 2009 ). It was found that in mice, even just one session of exercise increased BDNF levels. This effect, however, became amplified following a period of exercise in mice that regularly exercised, with an increased response in BDNF levels relative to mice after just a single session of exercise ( Johnson et al., 2003 ; van Praag et al., 2005 ; Rasmussen et al., 2009 ). Consistent with these findings is a meta-analysis of 29 studies spanning 1,111 human participants that analyzed BDNF expression levels across various exercise paradigms. However, many of the studies only examined moderate exercise, and several studies did not report intensity level. Interestingly, considerable evidence from this meta-analysis suggests that humans also experience a dose-response relationship in which each session of exercise corresponds to a dose of increased BDNF expression. Furthermore, regular exercise in moderate amounts has been shown to increase the magnitude of BDNF expression following individual sessions of exercise ( Szuhany et al., 2015 ).
There is not a perfect positive correlation, however, between the amount and intensity of exercise and BDNF expression levels and subsequent health benefits. Extreme exercise has been shown to disrupt a number of metabolic and physiological processes and lead to impaired cognitive performance in humans ( Aguiló et al., 2005 ). Since oxygen is rapidly metabolized during physical exertion, reactive oxygen species (ROS) are naturally produced as a metabolic byproduct. When produced at high levels, such as during bouts of intense exercise, ROS can lead to oxidative damage and increased cellular mortality in both rodents and humans ( Radak et al., 2016 ). Moderate levels of exercise enforce the human body’s antioxidant defense system, but extreme levels of exercise lead to the generation of more ROS than the antioxidant system can defend against, thereby allowing their accumulation as oxidative stress ( Mastaloudis et al., 2001 ). In fact, when treated with hydrogen peroxide, a potent ROS, hippocampal cell cultures taken from rodents showed an inverse relationship between BDNF expression levels and hydrogen peroxide concentration ( Kwon et al., 2013 ). The in vivo production of BDNF as a function of ROS production, however, is less clear and warrants further study.
Not all BDNF is created equal
In humans there are frequent polymorphisms in the BDNF gene which are typically found on position 66 that converts valine to a methionine. Previous work in the early 2000s suggested that somehow this gene was not working well in people with schizophrenia and that this Met66 polymorphism would be linked to disorders of the brain including schizophrenia.
When researchers examined the polymorphisms in the gene and schizophrenia and effect on hippocampal dysfunction in a study of 641 individuals reported in Cell 2003 by Egan et al. cohorts of schizophrenia, siblings and normal individuals were examined to see if there was a relationship. However, it turned out that this polymorphism had no difference on cognitive recall skills in individuals with schizophrenia but normal individuals (i.e. their siblings) who did not have symptoms showed dramatically reduced memory recall with the Met66 mutation. Later research showed that this polymorphism makes it harder to release BDNF, therefore affecting neuronal health. So even if an individual exercised, there is no guarantee that more BDNF will be released! The effectiveness of exercise is literally in your BDNF genes!


It may seem obvious that there are a multitude of cultural differences between societies in the world. After all, we can easily see that people vary from one society to the next. It’s natural that a young woman from rural Kenya would have a very different view of the world from an elderly man in Mumbai—one of the most populated cities in the world. Additionally, each culture has its own internal variations. Sometimes the differences between cultures are not nearly as large as the differences inside cultures.
High Culture and Popular Culture
Do you prefer listening to opera or hip hop music? Do you like watching horse racing or NASCAR? Do you read books of poetry or celebrity magazines? In each pair, one type of entertainment is considered high-brow and the other low-brow. Sociologists use the termhigh culture to describe the pattern of cultural experiences and attitudes that exist in the highest class segments of a society. People often associate high culture with intellectualism, political power, and prestige. In America, high culture also tends to be associated with wealth. Events considered high culture can be expensive and formal—attending a ballet, seeing a play, or listening to a live symphony performance.
The term popular culture refers to the pattern of cultural experiences and attitudes that exist in mainstream society. Popular culture events might include a parade, a baseball game, or the season finale of a television show. Rock and pop music—“pop” is short for “popular”—are part of popular culture. Popular culture is often expressed and spread via commercial media such as radio, television, movies, the music industry, publishers, and corporate-run websites. Unlike high culture, popular culture is known and accessible to most people. You can share a discussion of favorite football teams with a new coworker or comment on
American Idol
when making small talk in line at the grocery store. But if you tried to launch into a deep discussion on the classical Greek play
Antigone
, few members of U.S. society today would be familiar with it.
Although high culture may be viewed as superior to popular culture, the labels of high culture and popular culture vary over time and place. Shakespearean plays, considered pop culture when they were written, are now part of our society’s high culture. Five hundred years from now, will our descendants associate
Breaking Bad
with the cultural elite?
Subculture and Counterculture
A subculture is just what it sounds like—a smaller cultural group within a larger culture; people of a subculture are part of the larger culture but also share a specific identity within a smaller group.
Thousands of subcultures exist within the United States. Ethnic and racial groups share the language, food, and customs of their heritage. Other subcultures are united by shared experiences. Biker culture revolves around a dedication to motorcycles. Some subcultures are formed by members who possess traits or preferences that differ from the majority of a society’s population. The body modification community embraces aesthetic additions to the human body, such as tattoos, piercings, and certain forms of plastic surgery. In the United States, adolescents often form subcultures to develop a shared youth identity. Alcoholics Anonymous offers support to those suffering from alcoholism. But even as members of a subculture band together, they still identify with and participate in the larger society.
Sociologists distinguish subcultures from countercultures, which are a type of subculture that rejects some of the larger culture’s norms and values. In contrast to subcultures, which operate relatively smoothly within the larger society, countercultures might actively defy larger society by developing their own set of rules and norms to live by, sometimes even creating communities that operate outside of greater society.
Cults, a word derived from culture, are also considered counterculture group. The group “Yearning for Zion” (YFZ) in Eldorado, Texas, existed outside the mainstream and the limelight, until its leader was accused of statutory rape and underage marriage. The sect’s formal norms clashed too severely to be tolerated by U.S. law, and in 2008, authorities raided the compound and removed more than two hundred women and children from the property.
THE EVOLUTION OF AMERICAN HIPSTER SUBCULTURE
Skinny jeans, chunky glasses, and T-shirts with vintage logos—the American hipster is a recognizable figure in the modern United States. Based predominately in metropolitan areas, sometimes clustered around hotspots such as the Williamsburg neighborhood in New York City, hipsters define themselves through a rejection of the mainstream. As a subculture, hipsters spurn many of the values and beliefs of U.S. culture and prefer vintage clothing to fashion and a bohemian lifestyle to one of wealth and power. While hipster culture may seem to be the new trend among young, middle-class youth, the history of the group stretches back to the early decades of the 1900s.
Where did the hipster culture begin? In the early 1940s, jazz music was on the rise in the United States. Musicians were known as “hepcats” and had a smooth, relaxed quality that went against upright, mainstream life. Those who were “hep” or “hip” lived by the code of jazz, while those who were “square” lived according to society’s rules. The idea of a “hipster” was born.
The hipster movement spread, and young people, drawn to the music and fashion, took on attitudes and language derived from the culture of jazz.  When hipsters said, “It’s cool, man,” they meant not that everything was good, but that it was the way it was.
In the 1940s, U.S. hipsters were associated with the “cool” culture of jazz. (Photo courtesy of William P. Gottlieb/Ira and Leonore S. Gershwin Fund Collection, Music Division, Library of Congress)
By the 1950s, the jazz culture was winding down and many traits of hepcat culture were becoming mainstream. A new subculture was on the rise. The “Beat Generation,” a title coined by writer Jack Kerouac, were anticonformist and antimaterialistic. They were writers who listened to jazz and embraced radical politics. They bummed around, hitchhiked the country, and lived in squalor.
The lifestyle spread. College students, clutching copies of Kerouac’s
On the Road
, dressed in berets, black turtlenecks, and black-rimmed glasses.  Herb Caen, a San Francisco journalist, used the suffix from
Sputnik 1
, the Russian satellite that orbited Earth in 1957, to dub the movement’s followers “Beatniks.”
As the Beat Generation faded, a new, related movement began. It too focused on breaking social boundaries, but it also advocated freedom of expression, philosophy, and love. It took its name from the generations before; in fact, some theorists claim that Beats themselves coined the term to describe their children. Over time, the “little hipsters” of the 1970s became known simply as “hippies.”
Today’s generation of hipsters rose out of the hippie movement in the same way that hippies rose from Beats and Beats from hepcats. Although contemporary hipsters may not seem to have much in common with 1940s hipsters, the emulation of nonconformity is still there. In 2010, sociologist Mark Greif set about investigating the hipster subculture of the United States and found that much of what tied the group members together was not based on fashion, musical taste, or even a specific point of contention with the mainstream. “All hipsters play at being the inventors or first adopters of novelties,” Greif wrote. “Pride comes from knowing, and deciding, what’s cool in advance of the rest of the world. Yet the habits of hatred and accusation are endemic to hipsters because they feel the weakness of everyone’s position—including their own” (Greif 2010). Much as the hepcats of the jazz era opposed common culture with carefully crafted appearances of coolness and relaxation, modern hipsters reject mainstream values with a purposeful apathy.
Young people are often drawn to oppose mainstream conventions, even if in the same way that others do. Ironic, cool to the point of noncaring, and intellectual, hipsters continue to embody a subculture, while simultaneously impacting mainstream culture.
Intellectual and trendy, today’s hipsters define themselves through cultural irony. (Photo courtesy of Lorena Cupcake/Wikimedia Commons)
Cultural Change
As the hipster example illustrates, culture is always evolving. Moreover, new things are added to material culture every day, and they affect nonmaterial culture as well. Cultures change when something new (say, railroads or smartphones) opens up new ways of living and when new ideas enter a culture (say, as a result of travel or globalization).
Innovation: Discovery and Invention
An innovation refers to an object or concept’s initial appearance in society—it’s innovative because it is markedly new. There are two ways to come across an innovative object or idea: discover it or invent it. Discoveries make known previously unknown but existing aspects of reality. In 1610, when Galileo looked through his telescope and discovered Saturn, the planet was already there, but until then, no one had known about it. When Christopher Columbus encountered America, the land was, of course, already well known to its inhabitants. However, Columbus’s discovery was new knowledge for Europeans, and it opened the way to changes in European culture, as well as to the cultures of the discovered lands. For example, new foods such as potatoes and tomatoes transformed the European diet, and horses brought from Europe changed hunting practices of Native American tribes of the Great Plains.
Inventions result when something new is formed from existing objects or concepts—when things are put together in an entirely new manner. In the late 1800s and early 1900s, electric appliances were invented at an astonishing pace. Cars, airplanes, vacuum cleaners, lamps, radios, telephones, and televisions were all new inventions. Inventions may shape a culture when people use them in place of older ways of carrying out activities and relating to others, or as a way to carry out new kinds of activities. Their adoption reflects (and may shape) cultural values, and their use may require new norms for new situations.
Consider the introduction of modern communication technology, such as mobile phones and smartphones. As more and more people began carrying these devices, phone conversations no longer were restricted to homes, offices, and phone booths. People on trains, in restaurants, and in other public places became annoyed by listening to one-sided conversations. Norms were needed for cell phone use. Some people pushed for the idea that those who are out in the world should pay attention to their companions and surroundings. However, technology enabled a workaround: texting, which enables quiet communication and has surpassed phoning as the chief way to meet today’s highly valued ability to stay in touch anywhere, everywhere.
When the pace of innovation increases, it can lead to generation gaps. Technological gadgets that catch on quickly with one generation are sometimes dismissed by a skeptical older generation. A culture’s objects and ideas can cause not just generational but cultural gaps. Material culture tends to diffuse more quickly than nonmaterial culture; technology can spread through society in a matter of months, but it can take generations for the ideas and beliefs of society to change. Sociologist William F. Ogburn coined the term culture lag to refer to this time that elapses between the introduction of a new item of material culture and its acceptance as part of nonmaterial culture (Ogburn 1957).
Culture lag can also cause tangible problems. The infrastructure of the United States, built a hundred years ago or more, is having trouble supporting today’s more heavily populated and fast-paced life. Yet there is a lag in conceptualizing solutions to infrastructure problems. Rising fuel prices, increased air pollution, and traffic jams are all symptoms of culture lag. Although people are becoming aware of the consequences of overusing resources, the means to support changes takes time to achieve.
Sociologist Everett Rogers (1962) developed a model of the diffusion of innovations. As consumers gradually adopt a new innovation, the item grows toward a market share of 100 percent, or complete saturation within a society. (Graph courtesy of Tungsten/Wikimedia Commons)
Diffusion and Globalization
The integration of world markets and technological advances of the last decades have allowed for greater exchange between cultures through the processes of globalization and diffusion. Beginning in the 1980s, Western governments began to deregulate social services while granting greater liberties to private businesses. As a result, world markets became dominated by multinational companies in the 1980s, a new state of affairs at that time. We have since come to refer to this integration of international trade and finance markets as globalization. Increased communications and air travel have further opened doors for international business relations, facilitating the flow not only of goods but also of information and people as well (Scheuerman 2014 (revised)). Today, many U.S. companies set up offices in other nations where the costs of resources and labor are cheaper. When a person in the United States calls to get information about banking, insurance, or computer services, the person taking that call may be working in another country.
Alongside the process of globalization is diffusion, or the spread of material and nonmaterial culture. While globalization refers to the integration of markets, diffusion relates to a similar process in the integration of international cultures. Middle-class Americans can fly overseas and return with a new appreciation of Thai noodles or Italian gelato. Access to television and the Internet has brought the lifestyles and values portrayed in U.S. sitcoms into homes around the globe. Twitter feeds from public demonstrations in one nation have encouraged political protesters in other countries. When this kind of diffusion occurs, material objects and ideas from one culture are introduced into another.
Officially patented in 1893 as the “clasp locker” (left), the zipper did not diffuse through society for many decades. Today, it is immediately recognizable around the world. (Photo (a) courtesy of U.S. Patent Office/Wikimedia Commons; Photo (b) courtesy of Rabensteiner/Wikimedia Commons)
Summary
Sociologists recognize high culture and popular culture within societies. Societies are also comprised of many subcultures—smaller groups that share an identity. Countercultures reject mainstream values and create their own cultural rules and norms. Through invention or discovery, cultures evolve via new ideas and new ways of thinking. In many modern cultures, the cornerstone of innovation is technology, the rapid growth of which can lead to cultural lag. Technology is also responsible for the spread of both material and nonmaterial culture that contributes to globalization.
Section Quiz
-
An example of high culture is ___________, whereas an example of popular culture would be ____________.
-
Dostoevsky style in film; “American Idol” winners
-
medical marijuana; film noir
-
country music; pop music
-
political theory; sociological theory
-
Answer
-
A
-
The Ku Klux Klan is an example of what part of culture?
-
Counterculture
-
Subculture
-
Multiculturalism
-
Afrocentricity
-
Answer
-
A
-
Modern-day hipsters are an example of:
-
ethnocentricity
-
counterculture
-
subculture
-
high culture
-
Answer
-
C
-
Your eighty-three-year-old grandmother has been using a computer for some time now. As a way to keep in touch, you frequently send emails of a few lines to let her know about your day. She calls after every email to respond point by point, but she has never emailed a response back. This can be viewed as an example of:
-
cultural lag
-
innovation
-
ethnocentricity
-
xenophobia
-
Answer
-
A
-
Some jobs today advertise in multinational markets and permit telecommuting in lieu of working from a primary location. This broadening of the job market and the way that jobs are performed can be attributed to:
-
cultural lag
-
innovation
-
discovery
-
globalization
-
Answer
-
D
-
The major difference between invention and discovery is:
-
Invention is based on technology, whereas discovery is usually based on culture
-
Discovery involves finding something that already exists, but invention puts things together in a new way
-
Invention refers to material culture, whereas discovery can be material or theoretic, like laws of physics
-
Invention is typically used to refer to international objects, whereas discovery refers to that which is local to one’s culture
-
Answer
-
B
-
That McDonald’s is found in almost every country around the world is an example of:
-
globalization
-
diffusion
-
culture lag
-
xenocentrism
-
Answer
-
B
Short Answer
-
Identify several examples of popular culture and describe how they inform larger culture. How prevalent is the effect of these examples in your everyday life?
-
Consider some of the specific issues or concerns of your generation. Are any ideas countercultural? What subcultures have emerged from your generation? How have the issues of your generation expressed themselves culturally? How has your generation made its mark on society’s collective culture?
-
What are some examples of cultural lag that are present in your life? Do you think technology affects culture positively or negatively? Explain.
Further Research
The Beats were a counterculture that birthed an entire movement of art, music, and literature—much of which is still highly regarded and studied today. The man responsible for naming the generation was Jack Kerouac; however, the man responsible for introducing the world to that generation was John Clellon Holmes, a writer often lumped in with the group. In 1952 he penned an article for the
New York Times Magazine
titled, “This Is the Beat Generation.” Read that article and learn more about Clellon Holmes and the Beats: openstaxcollege.org/l/The-Beats
Popular culture meets counterculture in this as Oprah Winfrey interacts with members of the Yearning for Zion cult. Read about it here: openstaxcollege.org/l/Oprah
References
-
Greif, Mark. 2010. “The Hipster in the Mirror.”
New York Times
, November 12. Retrieved February 10, 2012 (
http://www.nytimes.com/2010/11/14/bo...l?pagewanted=1
).
-
Ogburn, William F. 1957. “Cultural Lag as Theory.”
Sociology & Social
Research
41(3):167–174.
-
Rogers, Everett M. 1962.
Diffusion of Innovations
. Glencoe: Free Press.
-
Scheuerman, William. 2010. “Globalization.”
The Stanford Encyclopedia of Philosophy
, edited by E. N. Revised 2014. Zalta, Summer. Retrieved February 10, 2012 (
http://plato.stanford.edu/archives/s...globalization/
).
Glossary
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countercultures
-
groups that reject and oppose society’s widely accepted cultural patterns
-
culture lag
-
the gap of time between the introduction of material culture and nonmaterial culture’s acceptance of it
-
diffusion
-
the spread of material and nonmaterial culture from one culture to another
-
discoveries
-
things and ideas found from what already exists
-
globalization
-
the integration of international trade and finance markets
-
high culture
-
the cultural patterns of a society’s elite
-
innovations
-
new objects or ideas introduced to culture for the first time
-
inventions
-
a combination of pieces of existing reality into new forms
-
popular culture
-
mainstream, widespread patterns among a society’s population
-
subcultures
-
groups that share a specific identification, apart from a society’s majority, even as the members exist within a larger society