Question 1

A puck moves on a horizontal air table. It is attached to a string that passes through a hole in the center of the table. As the puck rotates about the hole, the string is pulled downward very slowly and shortens the radius of rotation, so the puck gradually spirals in towards the center. By what factor will the puck's angular speed have changed when the string's length has decreased to one-half of its original length?

Accepted Answer

A)   2
B)   4
C)    2\sqrt { 2 }2c-2.7,0,-7.17,-2.7,-13.5,-8c-5.8,-5.3,-9.5,-10,-9.5,-14c0,-2,0.3,-3.3,1,-4c1.3,-2.7,23.83,-20.7,67.5,-54c44.2,-33.3,65.8,-50.3,66.5,-51c1.3,-1.3,3,-2,5,-2c4.7,0,8.7,3.3,12,10s173,378,173,378c0.7,0,35.3,-71,104,-213c68.7,-142,137.5,-285,206.5,-429c69,-144,104.5,-217.7,106.5,-221l0 -0c5.3,-9.3,12,-14,20,-14H400000v40H845.2724s-225.272,467,-225.272,467s-235,486,-235,486c-2.7,4.7,-9,7,-19,7c-6,0,-10,-1,-12,-3s-194,-422,-194,-422s-65,47,-65,47zM834 80h400000v40h-400000z'/>​ 
D)   1
E)   1/2 F) A) and D)
G) A) and B)

Question 2

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

Accepted Answer

A)   moving backward.
B)   stationary.
C)   moving forward.D) All of the above
E) B) and C)

Question 3

In a certain cyclotron, a proton of mass 1.67 × 10-27 kg moves in a circle of diameter 1.6 m with an angular speed of 2.0 × 106 rad/s. What is the angular momentum of the proton?

Accepted Answer

A)   1.3 × 10-21 kg ∙ m2/s
B)   1.8 × 10-21 kg ∙ m2/s
C)   2.1 × 10-21 kg ∙ m2/s
D)   3.2 × 10-21 kg ∙ m2/sE) A) and C)
F) A) and D)

Question 4

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?

Accepted Answer

The answer of An 80-kg man is skating northward and...

Question 5

A 1200-kg ore cart is rolling at 10.8 m/s across a flat friction-free surface. A crane suddenly drops  858 kg858 \mathrm {~kg}858 kg  of ore vertically into the cart. How fast does the cart move just after being loaded with the ore?

Accepted Answer

A)   6.30 m/s
B)   3.80 m/s
C)   4.20 m/s
D)   5.70 m/s E) All of the above
F) None of the above

Question 6

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?

Accepted Answer

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-axisF) C) and E)
G) A) and C)

Question 7

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?

Accepted Answer

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-axisF) None of the above
G) A) and E)

Question 8

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?

Accepted Answer

The answer of A batter applies an average force of...

Question 9

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?

Accepted Answer

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

Question 10

A solid wood door, 90.0 cm wide by 2.00 m tall has a mass of 35.0 kg. It is open and at rest. A small 500-g ball is thrown perpendicular to the door with a speed of 20.0 m/s and hits the door 60.0 cm from the hinged side. The ball rebounds with a speed of 16.0 m/s along the same line. What is the angular speed of the door just after the collision with the ball?

Accepted Answer

A)   0.127 rad/s
B)   0.925 rad/s
C)   1.14 rad/s
D)   2.28 rad/s
E)   4.57 rad/sF) B) and C)
G) A) and B)

Question 11

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.)

Accepted Answer

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.F) A) and E)
G) B) and E)

Question 12

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

Accepted Answer

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.F) A) and B)
G) B) and D)

Question 13

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

Accepted Answer

The answer of What is the magnitude of the momentum...

Question 14

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?

Accepted Answer

The answer of A 475-gram ball is traveling horizontally at...

Question 15

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?

Accepted Answer

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.E) All of the above
F) A) and B)

Question 16

A 5.0-m radius playground merry-go-round with a moment of inertia of 2000 kg ∙ m2 is rotating freely with an angular speed of 1.0 rad/s. Two people, each of mass 60 kg, are standing right outside the edge of the merry-go-round and suddenly step onto the edge with negligible speed relative to the ground. What is the angular speed of the merry-go-round right after the two people have stepped on?

Accepted Answer

A)   0.20 rad/s
B)   0.40 rad/s
C)   0.60 rad/s
D)   0.80 rad/s
E)   0.67 rad/sF) B) and D)
G) B) and E)

Question 17

A 1200-kg cannon suddenly fires a   100-kg 	ext { 100-kg } 100-kg   cannonball at  35 m/s35 \mathrm {~m} / \mathrm { s }35 m/s  What is the recoil speed of the cannon? Assume that frictional forces are negligible and the cannon is fired horizontally.

Accepted Answer

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

Question 18

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?

Accepted Answer

The answer of A 2200-kg auto moving northward at 12.0...

Question 19

Two dogs, Rover and Fido, run on a level frictionless surface. Rover runs eastward with a momentum of 24 kg . m/s, and Fido runs northward with momentum 10 kg . m/s. They make a sudden perfectly inelastic collision. What is the magnitude of their combined momentum after the collision?

Accepted Answer

A)   14 kg . m/s
B)   26 kg . m/s
C)   34 kg . m/s
D)   It cannot be determined without knowing the masses and velocities of the dogs.E) C) and D)
F) B) and D)

Question 20

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  0.81 ms0.81 \mathrm {~ms}0.81 ms  what is the average force exerted on the ball by the club?

Accepted Answer

A)   6.3 kN
B)   7.1 kN
C)   5.5 kN
D)   4.9 kN E) All of the above
F) None of the above

Exam 9: Momentum

Correct Answer
verified

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?

Correct Answer
verified

Correct Answer
verified

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

Correct Answer
verified

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?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

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?

Correct Answer
verified

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?

Correct Answer
verified

Correct Answer
verified

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?

Correct Answer
verified

In a certain cyclotron, a proton of mass 1.67 × 10^-27 kg moves in a circle of diameter 1.6 m with an angular speed of 2.0 × 10⁶ rad/s. What is the angular momentum of the proton?

Correct Answer
verified

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 $0.81 \mathrm {~ms}$ what is the average force exerted on the ball by the club?

Correct Answer
verified

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

Correct Answer
verified

A 1200-kg ore cart is rolling at 10.8 m/s across a flat friction-free surface. A crane suddenly drops $858 \mathrm {~kg}$ of ore vertically into the cart. How fast does the cart move just after being loaded with the ore?

Correct Answer
verified

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.)

Correct Answer
verified

A 1200-kg cannon suddenly fires a $\text { 100-kg }$ cannonball at $35 \mathrm {~m} / \mathrm { s }$ What is the recoil speed of the cannon? Assume that frictional forces are negligible and the cannon is fired horizontally.

Correct Answer
verified

Correct Answer
verified

Two dogs, Rover and Fido, run on a level frictionless surface. Rover runs eastward with a momentum of 24 kg . m/s, and Fido runs northward with momentum 10 kg . m/s. They make a sudden perfectly inelastic collision. What is the magnitude of their combined momentum after the collision?

Correct Answer
verified

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

Correct Answer
verified

Exam 9: Momentum

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

In a certain cyclotron, a proton of mass 1.67 × 10-27 kg moves in a circle of diameter 1.6 m with an angular speed of 2.0 × 106 rad/s. What is the angular momentum of the proton?

Correct AnswerverifiedShow Answer

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 0.81 ms0.81 \mathrm {~ms}0.81 ms what is the average force exerted on the ball by the club?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A 1200-kg ore cart is rolling at 10.8 m/s across a flat friction-free surface. A crane suddenly drops 858 kg858 \mathrm {~kg}858 kg of ore vertically into the cart. How fast does the cart move just after being loaded with the ore?

Correct AnswerverifiedShow Answer

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.)

Correct AnswerverifiedShow Answer

A 1200-kg cannon suddenly fires a 100-kg \text { 100-kg } 100-kg cannonball at 35 m/s35 \mathrm {~m} / \mathrm { s }35 m/s What is the recoil speed of the cannon? Assume that frictional forces are negligible and the cannon is fired horizontally.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Two dogs, Rover and Fido, run on a level frictionless surface. Rover runs eastward with a momentum of 24 kg . m/s, and Fido runs northward with momentum 10 kg . m/s. They make a sudden perfectly inelastic collision. What is the magnitude of their combined momentum after the collision?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

In a certain cyclotron, a proton of mass 1.67 × 10^-27 kg moves in a circle of diameter 1.6 m with an angular speed of 2.0 × 10⁶ rad/s. What is the angular momentum of the proton?

Correct Answer
verified

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 $0.81 \mathrm {~ms}$ what is the average force exerted on the ball by the club?

Correct Answer
verified

Correct Answer
verified

A 1200-kg ore cart is rolling at 10.8 m/s across a flat friction-free surface. A crane suddenly drops $858 \mathrm {~kg}$ of ore vertically into the cart. How fast does the cart move just after being loaded with the ore?

Correct Answer
verified

Correct Answer
verified

A 1200-kg cannon suddenly fires a $\text { 100-kg }$ cannonball at $35 \mathrm {~m} / \mathrm { s }$ What is the recoil speed of the cannon? Assume that frictional forces are negligible and the cannon is fired horizontally.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
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