Deck 9: Momentum

Question 1

Which of the following quantities are units of impulse? (There could be more than one correct choice.)

A) N ∙ m
B) kg ∙ s/m
C) kg ∙ m/s
D) N ∙ s
E) kg ∙ m²/s²

Answer 1

C, D

Question 2

In a collision between two unequal masses, which mass receives a greater magnitude impulse?

A) the larger mass
B) the smaller mass
C) They receive equal impulses.

Answer 2

C

Question 3

A rubber ball and a lump of clay have equal mass. They are thrown with equal speed against a wall. The ball bounces back with nearly the same speed with which it hit. The clay sticks to the wall. Which one of these objects experiences the greater momentum change?

A) the ball
B) the clay
C) Both of them experience the same non-zero momentum change.
D) Both of them experience zero momentum change.

Answer 3

A

Question 4

A rocket explodes into two fragments, one 25 times heavier than the other. The magnitude of the momentum change of the lighter fragment is

A) 25 times as great as the momentum change of the heavier fragment.
B) The same as the momentum change of the heavier fragment.
C) 1/25 as great as the momentum change of the heavier fragment.
D) 5 times as great as the momentum change of the heavier fragment.
E) 1/4 as great as the momentum change of the heavier fragment.

Question 5

A tiger is running in a straight line. If we double both the mass and speed of the tiger, the magnitude of its momentum will increase by what factor?

A)
B) 2
C) 4
D) 8
E) 16

Question 6

During World War I, Germany used a "Big Bertha" cannon to hurl shells into Paris 30 miles away. This gun also had a very long barrel. What was the reason for using a long barrel in these guns?

A) to exert a larger force on the shells
B) to reduce frictional losses
C) to allow the force of the expanding gases from the gunpowder to act for a longer time
D) to increase the force exerted on the bullet due to the expanding gases from the gunpowder
E) to reduce the force exerted on the bullet due to the expanding gases from the gunpowder

Question 7

Three cars, car X, car Y, and car Z, begin accelerating from rest at the same time. Car X is more massive than car Y, which is more massive than car Z. The net accelerating force exerted on each car is identical. After 10 seconds, which car has the most amount of momentum?

A) They all have the same amount of momentum.
B) Car X
C) Car Y
D) Car Z

Question 8

A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the momentum change during the collision is correct? (There could be more than one correct choice.)

A) The truck experiences the greater magnitude momentum change.
B) The small car experiences the greater magnitude momentum change.
C) The small car and the truck experience the same magnitude momentum change.
D) The magnitude of the momentum change experienced by each one is inversely proportional to its mass.
E) The magnitude of the momentum change experienced by each one is directly proportional to its mass.

Question 9

Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving 30 mph and crash head-on into a stationary brick wall. In neither case does your car bounce back from the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greater impact force on your car?

A) hitting the other car
B) hitting the brick wall
C) The force would be the same in both cases.
D) None of the above choices are correct.

Question 10

A very light ping-pong ball moving east at a speed of 4 m/s collides with a very heavy stationary bowling ball. The Ping-Pong ball bounces back to the west, and the bowling ball moves very slowly to the east. Which object experiences the greater magnitude impulse during the collision?

A) Neither; both experienced the same magnitude impulse.
B) the Ping-Pong ball
C) the bowling ball
D) It is impossible to tell since the actual mass values are not given.
E) It is impossible to tell since the velocities after the collision are unknown.

Question 11

Identical forces act for the same length of time on two different objects. The magnitude of the change in momentum of the lighter object is

A) smaller than the magnitude of the change in momentum of the larger mass, but not zero.
B) larger than the magnitude of the change in momentum of the larger mass.
C) exactly equal to the magnitude of the change in momentum of the larger mass.
D) zero.
E) There is not enough information to answer the question.

Question 12

A very elastic rubber ball is dropped from a certain height and hits the floor with a downward speed v. Since it is so elastic, the ball bounces back with the same speed v going upward. Which of the following statements about the bounce are correct? (There could be more than one correct choice.)

A) The ball had the same momentum just before and just after the bounce.
B) The magnitude of the ball's momentum was the same just before and just after the bounce.
C) The ball's momentum was conserved during the bounce.
D) None of the above statements are correct.

Question 13

A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the average force during the collision is correct?

A) The truck experiences the greater average force.
B) The small car experiences the greater average force.
C) The small car and the truck experience the same average force.
D) The force experienced by each one is inversely proportional to its mass.
E) The force experienced by each one is directly proportional to its mass.

Question 14

The momentum of an isolated system is conserved

A) only in inelastic collisions.
B) only in elastic collisions.
C) in both elastic and inelastic collisions.

Question 15

A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the momentum during the collision are correct? (There could be more than one correct choice.)

A) The momentum of the truck is conserved.
B) The momentum of the car is conserved.
C) The car and the truck must undergo the same change in speed.
D) The momentum of the car and the momentum of the truck are each conserved.
E) The momentum of the car-truck system is conserved, but the momentum of each one separately is not conserved.

Question 16

Two friends are standing on opposite ends of a canoe that is initially at rest with respect to a frictionless lake. The person in the front throws a very massive ball toward the back, and the person in the back catches it. After the ball is caught, the canoe is

A) moving backward.
B) stationary.
C) moving forward.

Question 17

Which of the following quantities are units of momentum? (There could be more than one correct choice.)

A) N ∙ m
B) kg ∙ s/m
C) kg ∙ m/s
D) N ∙ s
E) kg ∙ m²/s²

Question 18

A 5-kg ball collides inelastically head-on with a 10-kg ball, which is initially stationary. Which of the following statements is true? (There could be more than one correct choice.)

A) The magnitude of the change of velocity the 5-kg ball experiences is greater than that of the 10-kg ball.
B) The magnitude of the change of velocity the 5-kg ball experiences is less than that of the 10-kg ball.
C) The magnitude of the change of velocity the 5-kg ball experiences is equal to that of the 10-kg ball.
D) The magnitude of the change of the momentum of the 5-kg ball is equal to the magnitude of the change of momentum of the 10-kg ball.
E) Both balls lose all their momentum since the collision is inelastic.

Question 19

You are standing on a skateboard, initially at rest. A friend throws a very heavy ball towards you. You have two choices about what to do with the ball: either catch the ball or deflect it back toward your friend with the same speed as it was originally thrown. Which choice should you make in order to maximize your speed on the skateboard?

A) Catch the ball.
B) Deflect the ball back.
C) Your final speed on the skateboard will be the same regardless whether you catch the ball or deflect the ball.

Question 20

In an inelastic collision involving an isolated system, the final total momentum is

A) exactly the same as the initial momentum.
B) more than the initial momentum.
C) less than the initial momentum.

Question 21

A 60-kg swimmer suddenly dives horizontally from a 150-kg raft with a speed of 1.5 m/s. The raft is initially at rest. What is the speed of the raft immediately after the diver jumps if the water has negligible effect on the raft?

Question 22

A 2.0-kg ball moving eastward at 3.0 m/s suddenly collides with and sticks to a 4.0-kg ball moving northward at 2.0 m/s. What is the magnitude of the momentum of this system just after the collision?

A) 14 kg ∙ m/s
B) 2.0 kg ∙ m/s
C) 10 kg ∙ m/s
D) 6.0 kg ∙ m/s
E) 8.0 kg ∙ m/s

Question 23

Two air track carts move along an air track towards each other. Cart A has a mass of 450 g and moves toward the right with a speed of 0.850 m/s. Cart B has a mass of 300 g and moves toward the left with a speed of 1.12 m/s. What is the total momentum of the two-cart system?

A) 0.047 kg ∙ m/s toward the right
B) 0.719 kg ∙ m/s toward the right
C) 0.719 kg ∙ m/s toward the left
D) 0.750 kg ∙ m/s toward the right
E) 0.750 kg ∙ m/s toward the left

Question 24

A 0.14-kg baseball is dropped from rest from a height of 2.0 m above the ground. What is the magnitude of its momentum just before it hits the ground if we neglect air resistance?

A) 0.28 kg ∙ m/s
B) 0.88 kg ∙ m/s
C) 0.44 kg ∙ m/s
D) 0.62 kg ∙ m/s
E) 1.4 kg ∙ m/s

Question 25

A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms,

A) her moment of inertia decreases and her angular speed increases.
B) her moment of inertia decreases and her angular speed decreases.
C) her moment of inertia increases and her angular speed increases.
D) her moment of inertia increases and her angular speed decreases.
E) her moment of inertia increases and her angular speed remains the same.

Question 26

What is the magnitude of the momentum of a 0.140 kg baseball traveling at 45.0 m/s?

Question 27

A merry-go-round spins freely when Diego moves quickly to the center along a radius of the merry-go-round. As he does this, it is true to say that

A) the moment of inertia of the system decreases and the angular speed increases.
B) the moment of inertia of the system decreases and the angular speed decreases.
C) the moment of inertia of the system decreases and the angular speed remains the same.
D) the moment of inertia of the system increases and the angular speed increases.
E) the moment of inertia of the system increases and the angular speed decreases.

Question 28

Three objects are moving along a straight line as shown in the figure. Taking the positive direction to be to the right, what is the total momentum of this system?

A) +106 kg ∙ m/s
B) -106 kg ∙ m/s
C) +14.0 kg ∙ m/s
D) -14.0 kg ∙ m/s
E) 0.00 kg ∙ m/s

Question 29

An empty train car of mass 2.0 x 10⁴ kg coasts along at 10 m/s. A 3000-kg boulder is suddenly dropped vertically into the car. Find the speed of the car immediately after the boulder is dropped in.

Question 30

A 0.140-kg baseball is dropped and reaches a speed of 1.20 m/s just before it hits the ground and bounces. It rebounds with an upward velocity of 1.00 m/s. What is the change of the ball's momentum during the bounce?

A) 0.0280 kg ∙ m/s upwards
B) 0.0280 kg ∙ m/s downwards
C) 0.308 kg ∙ m/s upwards
D) 0.308 kg ∙ m/s downwards
E) 0.000 kg ∙ m/s

Question 31

A 600-kg car makes a 90° turn. Its speed before the turn is 21.0 m/s and after the turn it is 24.0 m/s. What is the magnitude of the change in the car's momentum during the turn?

A) 19.1 × 10³ kg∙m/s
B) 10.2 × 10³ kg∙m/s
C) 9.55 × 10³ kg∙m/s
D) 12.0 × 10³ kg∙m/s
E) 22.2 × 10³ kg∙m/s

Question 32

A 0.330-kg volleyball is thrown vertically downward with a speed of 0.150 m/s in a place where g = 9.81 m/s². It takes it 0.0655 s to reach the ground. What is the magnitude of its momentum just before it hits the ground?

A) 0.212 kg ∙ m/s
B) 0.262 kg ∙ m/s
C) 0.163 kg ∙ m/s
D) 0.0216 kg ∙ m/s
E) 0.0418 kg ∙ m/s

Question 33

In a police ballistics test, 2.00-g bullet traveling at 700 m/s suddenly hits and becomes embedded in a stationary 5.00-kg wood block. What is the speed of the block immediately after the bullet has stopped moving relative to the block?

Question 34

A 14,000-kg boxcar is coasting at 1.50 m/s along a horizontal track when it suddenly hits and couples with a stationary 10,000-kg boxcar. What is the speed of the cars just after the collision?

Question 35

A 100-g ball falls from a window that is 12 m above ground level and experiences no significant air resistance as it falls. What is its momentum when it strikes the ground?

A) 3.3 kg ∙ m/s
B) 4.8 kg ∙ m/s
C) 1.8 kg ∙ m/s
D) 1.5 kg ∙ m/s
E) 2.4 kg ∙ m/s

Question 36

A 328-kg car moving at 19.1 m/s in the +x direction hits from behind a second car moving at in the same direction. If the second car has a mass of and a speed of right after the collision, what is the velocity of the first car after this sudden collision?

A) 14.0 m/s
B) 18.2 m/s
C) 24.2 m/s
D) -14.0 m/s

Question 37

A 1200-kg ore cart is rolling at 10.8 m/s across a flat friction-free surface. A crane suddenly drops of ore vertically into the cart. How fast does the cart move just after being loaded with the ore?

A) 6.30 m/s
B) 3.80 m/s
C) 4.20 m/s
D) 5.70 m/s

Question 38

A firecracker breaks up into two pieces, one of which has a mass of 200 g and flies off along the +x-axis with a speed of 82.0 m/s. The second piece has a mass of 300 g and flies off along the +y-axis with a speed of 45.0 m/s. What is the total momentum of the two pieces?

A) 361 kg ∙ m/s at 56.3° from the +x-axis
B) 93.5 kg ∙ m/s at 28.8° from the +x-axis
C) 21.2 kg ∙ m/s at 39.5° from the +x-axis
D) 361 kg ∙ m/s at 0.983° from the +x-axis
E) 21.2 kg ∙ m/s at 56.3° from the +x-axis

Question 39

A 0.10-kg ball, traveling horizontally at 25 m/s, strikes a wall and rebounds at 19 m/s. What is the magnitude of the change in the momentum of the ball during the rebound?

A) 1.2 kg ∙ m/s
B) 1.8 kg ∙ m/s
C) 4.4 kg ∙ m/s
D) 5.4 kg ∙ m/s
E) 72 kg ∙ m/s

Question 40

Find the magnitude and direction of the net momentum of the system shown in the figure. Express the direction by giving the angle the net momentum makes with the +x-axis.

Question 41

Calculate the impulse due to a force of that lasts for

A) 6.3 kg∙ m/s
B) 5.0 kg∙ m/s
C) 5.7 kg∙ m/s
D) 6.9 kg∙ m/s

Question 42

A dinner plate falls vertically to the floor and breaks up into three pieces, which slide horizontally along the floor. Immediately after the impact, a 200-g piece moves along the +x-axis with a speed of 2.00 m/s, a 235-g piece moves along the +y-axis with a speed of 1.50 m/s. The third piece has a mass of 100 g. What is the speed of the third piece?

A) 2.51 m/s
B) 2.57 m/s
C) 3.50 m/s
D) 5.33 m/s
E) 6.83 m/s

Question 43

The graph in the figure shows the x component F of the net force that acts for 10 s on a 100-kg crate. What is the change in the momentum of the crate during the 10 s that this force acts?

A) -100 kg ∙ m/s
B) -25 kg ∙ m/s
C) 75 kg ∙ m/s
D) -75 kg ∙ m/s
E) 25 kg ∙ m/s

Question 44

Two ice skaters suddenly push off against one another starting from a stationary position. The 45-kg skater acquires a speed of 0.375 m/s relative to the ice. What speed does the 60-kg skater acquire relative to the ice?

A) 0.50 m/s
B) 0.28 m/s
C) 0.38 m/s
D) 0.75 m/s
E) 0.00 m/s

Question 45

A forklift pushes a 100-kg crate, starting from rest, with a horizontal force of magnitude F. The graph in the figure shows the x component of this force as a function of time. What is the instantaneous velocity of the crate at time t = 10 s?

A) 25 cm/s
B) 0.00 cm/s
C) 75 cm/s
D) -25 cm/s
E) -75 cm/s

Question 46

A 14-cm diameter champagne bottle rests on its side on top of a frictionless horizontal table. Suddenly, the cork pops and the bottle slides backward, covering a distance of in If the mass of the bottle is 500 times the mass of the cork, find the distance from the original position that the cork will land on the table. Neglect air resistance and assume that the cork is very small compared to the bottle.

A) 3000 cm
B) 60 m
C) 85 m
D) 8.5 cm

Question 47

A golf club exerts an average horizontal force of 1000 N on a 0.045-kg golf ball that is initially at rest on the tee. The club is in contact with the ball for 1.8 ms. What is the speed of the golf ball just as it leaves the tee?

A) 30 m/s
B) 35 m/s
C) 40 m/s
D) 45 m/s
E) 50 m/s

Question 48

Astronaut Jennifer's lifeline to her spaceship comes loose and she finds herself stranded, "floating" 100 m from the mothership. She suddenly throws her 2.00-kg wrench at 20 m/s in a direction away from the ship. If she and her spacesuit have a combined mass of 200 kg, how long does it take her to coast back to her spaceship?

A) 1000 s
B) 750 s
C) 500 s
D) 250 s
E) 2.50 min

Question 49

A 1200-kg cannon suddenly fires a cannonball at What is the recoil speed of the cannon? Assume that frictional forces are negligible and the cannon is fired horizontally.

A) 2.9 m/s
B) 35 m/s
C) 3.5 m/s
D) 3.2 m/s

Question 50

Two astronauts, of masses 60 kg and 80 kg, are initially right next to each other and at rest in outer space. They suddenly push each other apart. What is their separation after the heavier astronaut has moved 12 m?

A) 9.0 m
B) 16 m
C) 21 m
D) 24 m
E) 28 m

Question 51

A batter hits a 0.140-kg baseball that was approaching him at 30 m/s and, as a result, the ball leaves the bat at 40 m/s in the reverse of its original direction. The ball remains in contact with the bat for 2.0 ms. What is the magnitude of the average force exerted by the bat on the ball?

Question 52

A 0.17-kg baseball is thrown with a speed of 38 m/s and it is hit straight back toward the pitcher with a speed of 62 m/s. What is the magnitude of the impulse exerted upon the ball by the bat?

Question 53

A dinner plate falls vertically to the floor and breaks up into three pieces, which slide horizontally along the floor. Immediately after the impact, a 320-g piece moves along the +x-axis with a speed of 2.00 m/s and a 355-g piece moves along the +y-axis with a speed of 1.50 m/s. The third piece has a mass of 100 g. In what direction relative to the +x-axis does the third piece move?

A) 216.9° from the +x-axis
B) 219.8° from the +x-axis
C) 36.9° from the +x-axis
D) 39.9° from the +x-axis
E) 39.8° from the +x-axis

Question 54

Two astronauts, of masses 60 kg and 80 kg, are initially right next to each other and at rest in outer space. They suddenly push each other apart. How far has the heavier astronaut moved when the lighter astronaut has moved 12 m?

A) 16 m
B) 9.0 m
C) 21 m
D) 7.0 m
E) 12 m

Question 55

A batter applies an average force of 8000 N to a baseball for 1.1 ms. What is the magnitude of the impulse delivered to the baseball by the bat?

Question 56

A super dart of mass 20 g, traveling at 350 m/s, strikes a steel plate at an angle of 30° with the plane of the plate, as shown in the figure. It bounces off the plate at the same angle but at a speed of 320 m/s. What is the magnitude of the impulse that the plate gives to the bullet?

A) 0.52 N ∙ s
B) 4.3 N ∙ s
C) 300 N ∙ s
D) 6.7 N ∙ s
E) 0.30 N ∙ s

Question 57

Jennifer hits a stationary 0.20-kg ball, and it leaves her racket at 40 m/s. Time-lapse photography shows that the ball was in contact with the racket for 40 ms.
(a) What average force did the ball exert on the racket?
(b) What is the ratio of this force to the weight of the ball?

Question 58

A 0.140-kg baseball is thrown with a velocity of It is struck by the bat with an average force of 5000 N, which results in a velocity of 37.0 m/s in the opposite direction from the original velocity. How long were the bat and ball in contact?

A) 1.79 × 10^-3 s
B) 1.28 × 10^-2 s
C) 3.07 × 10^-2 s
D) 4.30 × 10^-3 s

Question 59

A girl of mass 55 kg throws a ball of mass 0.80 kg against a wall. The ball strikes the wall horizontally with a speed of and it bounces back with this same speed. The ball is in contact with the wall What is the magnitude of the average force exerted on the wall by the ball?

A) 800 N
B) 400 N
C) 55,000 N
D) 27,500 N
E) 13,750 N

Question 60

In a police ballistics test, a 10.0-g bullet moving at 300 m/s is fired into a 1.00-kg block at rest. The bullet goes through the block almost instantaneously and emerges with 50.0% of its original speed. What is the speed of the block just after the bullet emerges?

A) 1.50 m/s
B) 2.97 m/s
C) 3.00 m/s
D) 273 m/s

Question 61

A very small 51-g steel ball is released from rest and falls vertically onto a steel plate. The ball strikes the plate and is in contact with it for 0.50 ms. The ball rebounds elastically and returns to its original height. The total time interval for a round trip is 3.00 s. What is the magnitude of the average force exerted on the ball by the plate during contact with the plate?

A) 3000 N
B) 1500 N
C) 2490 N
D) 2000 N
E) 3500 N

Question 62

A 0.24 kg blob of clay is thrown at a wall with an initial horizontal velocity of If the clay comes to a stop in what is the average horizontal force on the clay due to the wall?

A) 42 N
B) 26 N
C) 35 N
D) 51 N

Question 63

An 80-kg man is skating northward and happens to suddenly collide with a 20-kg boy who is ice skating toward the east. Immediately after the collision, the man and boy are seen to be moving together at 2.5 m/s in a direction 60° north of east. How fast was the boy moving just before the collision?

Question 64

A car (of mass 1500 kg) and a small truck (of mass 2000 kg) collide suddenly at right angles at an icy intersection. The car was originally traveling eastward at 20.0 m/s and the truck was traveling northward at 20.0 m/s just before the collision took place. What is the speed of the combined wreck just after the collision if the vehicles become enmeshed?

Question 65

A 2.0-kg mass moving at 5.0 m/s suddenly collides head-on with a 3.0-kg mass at rest. If the collision is perfectly inelastic, what is the speed of the masses just after the collision?

A) 10 m/s
B) 2.5 m/s
C) 2.0 m/s
D) 0 m/s, since the collision is inelastic

Question 66

Two vehicles approach a right angle intersection and then suddenly collide. After the collision, they become entangled. If their mass ratios were 1:4 and their respective speeds as they approached the intersection were both 13 m/s, find the magnitude and direction of the final velocity of the wreck.

A) 11 m/s at 14° with respect to the original direction of the lighter car
B) 16 m/s at 76° with respect to the original direction of the lighter car
C) 11 m/s at 76° with respect to the original direction of the lighter car
D) 16 m/s at 14° with respect to the original direction of the lighter car

Question 67

A golf ball of mass 0.050 kg is at rest on the tee. Just after being struck, it has a velocity of 102 m/s. If the club and ball were in contact for what is the average force exerted on the ball by the club?

A) 6.3 kN
B) 7.1 kN
C) 5.5 kN
D) 4.9 kN

Question 68

A 1000-kg whale swims horizontally to the right at a speed of 6.0 m/s. It suddenly collides directly with a stationary seal of mass 200 kg. The seal grabs onto the whale and holds fast. What is the momentum of these two sea creatures just after their collision? You can neglect any drag effects of the water during the collision.

A) 0.00 kg ∙ m/s
B) 1200 kg ∙ m/s
C) 2000 kg ∙ m/s
D) 7200 kg ∙ m/s
E) 6000 kg ∙ m/s

Question 69

A block of mass m = 5.6 kg, moving on a frictionless surface with a velocity of to the right, collides with a block of mass M at rest, as shown in the figure. After the collision, the 5.6-kg block recoils with a velocity of to the left. If the blocks are in contact for 0.20 s, what is the magnitude of the average force on the 5.6-kg block, while the two blocks are in contact?

A) 202 N
B) 192 N
C) 182 N
D) 0 N
E) 0 N

Question 70

A fire hose is turned on the door of a burning building in order to knock the door down. This requires a force of 1000 N. If the hose delivers 40 kg of water per second, what is the minimum velocity of the stream needed to knock down the door, assuming the water doesn't bounce back?

A) 15 m/s
B) 20 m/s
C) 25 m/s
D) 30 m/s

Question 71

A 2200-kg auto moving northward at 12.0 m/s runs into a 3800-kg truck which is also moving northward, but at 5.00 m/s. If the vehicles lock bumpers, how fast are they moving just after the collision?

Question 72

A 1200-kg car moving at suddenly collides with a stationary car of mass If the two vehicles lock together, what is their combined velocity immediately after the collision?

A) 6.9 m/s
B) 8.6 m/s
C) 12.1 m/s
D) 5.5 m/s

Question 73

A 0.140 kg baseball is thrown horizontally with a velocity of 28.9 m/s. It is struck with a constant horizontal force that lasts for 1.85 ms, which results in a velocity of 37.0 m/s in the opposite direction. What was the magnitude of the horizontal force?

A) 0.613 kN
B) 2.19 kN
C) 2.80 kN
D) 4.99 kN

Question 74

A block of mass m = 34 kg and speed V is behind a block of mass M = 81 kg and speed of as shown in the figure. The surface is frictionless and the blocks collide and couple. After the collision, the blocks have a common speed of What is the magnitude of the impulse on the 34-kg block due to the collision?

A) 32 N ∙ s
B) 14 N ∙ s
C) 41 N ∙ s
D) 57 N ∙ s
E) 73 N ∙ s

Question 75

A 1000-kg whale swims horizontally to the right at a speed of 6.0 m/s. It suddenly collides directly with a stationary seal of mass 200 kg. The seal grabs onto the whale and holds fast. What is the speed of these two sea creatures just after their collision? You can neglect any drag effects of the water during the collision.

A) 0.00 m/s
B) 3.0 m/s
C) 4.0 m/s
D) 5.0 m/s
E) 6.0 m/s

Question 76

A batter hits a foul ball. The 0.14-kg baseball that was approaching him at 40 m/s leaves the bat at 30 m/s in a direction perpendicular to the line between the batter and the pitcher. What is the magnitude of the impulse delivered to the baseball?

A) 9.8 N ∙ s
B) 1.4 N ∙ s
C) 3.5 N ∙ s
D) 5.6 N ∙ s
E) 7.0 N ∙ s

Question 77

A force of 5.3 N is needed to hold on to an umbrella in a strong wind. If the air molecules each have a mass of 4.7 ×10^-26 kg, and each one strikes the umbrella (without rebounding) with a speed of 2.0 m/s in the same direction, how many atoms strike the umbrella each second? Assume that the wind blows horizontally so that the gravity can be neglected.

Question 78

A 475-gram ball is traveling horizontally at 12.0 m/s to the left when it is suddenly struck horizontally by a bat, causing it to reverse direction and initially travel at 8.50 m/s to the right. If the bat produced an average force of 1275 N on the ball, for how long (in milliseconds) was it in contact with the ball?

Question 79

A 0.140-kg baseball is dropped from rest. It has a speed of 1.20 m/s just before it hits the ground, and it rebounds with an upward speed of 1.00 m/s. The ball is in contact with the ground for 0.0140 s. What is the average force exerted by the ground on the ball during the time of contact?

A) 2.00 N upwards
B) 2.00 N downwards
C) 22.0 N upwards
D) 22.0 N downwards
E) 0.00 N

Question 80

A steady horizontal force lasting for 2.1 s gives a 1.25 kg object an acceleration of 3.2 m/s² on a frictionless table. What impulse does this force give to the object?

A) 26 kg ∙ m/s
B) 11 kg ∙ m/s
C) 8.4 kg ∙ m/s
D) 2.6 kg ∙ m/s