Question 1

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?

Accepted Answer

A)  2 
B)  4 
C)  16 
D)  $\sqrt { 2 }$ 
E)  8 
A)  2 
B)  4 
C)  16 
D)  $\sqrt { 2 }$ 
E)  8

Question 2

In a police rifle test, a 15-g bullet traveling  213 m/s in a vertical direction suddenly buries itself in a 2.4-kg block of wood at rest directly above it. As a result, the bullet-block combination moves vertically upward.
(a) Determine the velocity of the bullet-block combination just after the impact.
(b) Determine the maximum height reached by the bullet/block combination.
(c) Is kinetic energy conserved in this collision?

Accepted Answer

(a) 1.3 m/s (b) 0.08

Question 3

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?

Accepted Answer

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

Question 4

Three balls are moving along a straight line having the instantaneous positions shown in the figure. At that instant, find the location and velocity of the center of mass (or center of gravity) of this system.

Accepted Answer

7.00 m to the right

Question 5

In the figure, four point masses are placed as shown. Assume that all the numbers in the figure are accurate to two significant figures. What are the x and y coordinates of the center of mass (or center
Of gravity) of this arrangement?

Accepted Answer

A)   (2.2 m, 2.6 m) 
B)   (2.3 m, 2.7 m) 
C)   (2.3 m, 2.8 m) 
D)   (2.3 m, 2.6 m) 
E)   (2.2 m, 2.7 m) 
A)   (2.2 m, 2.6 m) 
B)   (2.3 m, 2.7 m) 
C)   (2.3 m, 2.8 m) 
D)   (2.3 m, 2.6 m) 
E)   (2.2 m, 2.7 m)

Question 6

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

Question 7

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)  $21.2 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s } \text { at } 56.3 ^ { \circ } \text { from the } + x \text {-axis }$ 
B)  $21.2 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s } \text { at } 39.5 ^ { \circ } \text { from the } + x \text {-axis }$ 
C)  $361 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s } \text { at } 56.3 ^ { \circ } \text { from the } + x \text {-axis }$ 
D)  $361 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s } \text { at } 0.983 ^ { \circ } \text { from the } + x \text {-axis }$ 
E)  $93.5 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s } \text { at } 28.8 ^ { \circ } \text { from the } + x \text {-axis }$ 
A)  $21.2 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s } \text { at } 56.3 ^ { \circ } \text { from the } + x \text {-axis }$ 
B)  $21.2 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s } \text { at } 39.5 ^ { \circ } \text { from the } + x \text {-axis }$ 
C)  $361 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s } \text { at } 56.3 ^ { \circ } \text { from the } + x \text {-axis }$ 
D)  $361 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s } \text { at } 0.983 ^ { \circ } \text { from the } + x \text {-axis }$ 
E)  $93.5 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s } \text { at } 28.8 ^ { \circ } \text { from the } + x \text {-axis }$

Question 8

A  320-g air track cart traveling at  1.25 m/s suddenly collides elastically with a stationary  270-g cart. What is the speed of the  270-g cart just after the collision?

Accepted Answer

A)   1.14 m/s 
B)   1.36 m/s 
C)   0.678 m/s 
D)   2.72 m/s 
E)   0.106 m/s 
A)   1.14 m/s 
B)   1.36 m/s 
C)   0.678 m/s 
D)   2.72 m/s 
E)   0.106 m/s

Question 9

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  25 m/s, and it bounces back with this same speed. The ball is in contact with the wall  0.050 s. What is the magnitude of the average force exerted on the wall by the ball?

Accepted Answer

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

Question 10

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?

Accepted Answer

A)  $0.28 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$ 
B)  $0.44 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$ 
C)  $0.62 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$ 
D)  $0.88 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$ 
E)  $1.4 \mathrm { kq } \cdot \mathrm { m } / \mathrm { s }$ 
A)  $0.28 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$ 
B)  $0.44 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$ 
C)  $0.62 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$ 
D)  $0.88 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$ 
E)  $1.4 \mathrm { kq } \cdot \mathrm { m } / \mathrm { s }$

Question 11

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.)

Accepted Answer

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

Question 12

A 2.0-m rope is lying on a table. You pick up one end and start raising it vertically. How high above the table is the center of mass (or center of gravity) of the rope when half of the rope has
Lifted off the table?

Accepted Answer

A)  0.50 m 
B)  1.5 m 
C)  1.0 m 
D)  0.25 m 
E)  0.75 m 
A)  0.50 m 
B)  1.5 m 
C)  1.0 m 
D)  0.25 m 
E)  0.75 m

Question 13

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?

Accepted Answer

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

Question 14

An 8.0-g bullet is suddenly shot into a 4.0-kg block that is at rest on a frictionless horizontal surface, as shown in the figure. The bullet remains lodged in the block. The block then moves
Against a spring and compresses it by 3.7 cm. The force constant (spring constant) of the spring is
2500 N/m. What was the initial speed $$\mathcal { V }$$ of the bullet?

Accepted Answer

A)   480 m/s 
B)   500 m/s 
C)   460 m/s 
D)   440 m/s 
E)   520 m/s 
A)   480 m/s 
B)   500 m/s 
C)   460 m/s 
D)   440 m/s 
E)   520 m/s

Question 15

In a certain nuclear reactor, neutrons suddenly collide with deuterons, which have twice the mass of neutrons. In a head-on elastic collision with a stationary deuteron, what fraction of the initial
Kinetic energy of a neutron is transferred to the deuteron?

Accepted Answer

A)  3/4 
B)  8/9 
C)  1/2 
D)  1/3 
E)  5/6 
A)  3/4 
B)  8/9 
C)  1/2 
D)  1/3 
E)  5/6

Question 16

Two simple pendulums of equal length l = 0.45 m are suspended from the same point. The pendulum bobs are small solid steel spheres. The first bob is drawn back to make a 35° angle with
The vertical, while the other one is left hanging at rest. If the first bob has a mass of 0.25 kg and the
Second has a mass of 0.54 kg, how high will the second bob rise above its initial position when
Struck elastically by the first bob after it is released?

Accepted Answer

A)  2.7 cm 
B)  3.3 cm 
C)  4.4 cm 
D)  3.9 cm 
A)  2.7 cm 
B)  3.3 cm 
C)  4.4 cm 
D)  3.9 cm

Question 17

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?

Accepted Answer

The answer of A car (of mass 1500 kg) and...

Question 18

In the figure, determine the character of the collision. The masses of the blocks, and the velocities before and after, are shown. The collision is

Accepted Answer

A)  completely inelastic. 
B)  partially inelastic. 
C)  perfectly elastic. 
D)  characterized by an increase in kinetic energy. 
E)  not possible because momentum is not conserved. 
A)  completely inelastic. 
B)  partially inelastic. 
C)  perfectly elastic. 
D)  characterized by an increase in kinetic energy. 
E)  not possible because momentum is not conserved.

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?

Accepted Answer

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

Question 20

Three small masses are positioned as follows: 2.0 kg at (0.0 m, 0.0 m), 2.0 kg at (2.0 m, 0.0 m), and 4.0 kg at (2.0 m, 1.0 m). Determine the coordinates of the center of mass (or center of gravity) of
This system.

Accepted Answer

A)  (0.50 m, 1.5 m) 
B)  (2.5 m, 1.5 m) 
C)  (1.5 m, 0.50 m) 
D)  (2.5 m, 0.50 m) 
A)  (0.50 m, 1.5 m) 
B)  (2.5 m, 1.5 m) 
C)  (1.5 m, 0.50 m) 
D)  (2.5 m, 0.50 m)

Exam 7: Linear Momentum

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 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?

Three balls are moving along a straight line having the instantaneous positions shown in the figure. At that instant, find the location and velocity of the center of mass (or center of gravity) of this system.

In the figure, four point masses are placed as shown. Assume that all the numbers in the figure are accurate to two significant figures. What are the x and y coordinates of the center of mass (or center Of gravity) of this arrangement?

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 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 320-g air track cart traveling at 1.25 m/s suddenly collides elastically with a stationary 270-g cart. What is the speed of the 270-g cart just after the collision?

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 25 m/s, and it bounces back with this same speed. The ball is in contact with the wall 0.050 s. What is the magnitude of the average force exerted on the wall by the ball?

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 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 2.0-m rope is lying on a table. You pick up one end and start raising it vertically. How high above the table is the center of mass (or center of gravity) of the rope when half of the rope has Lifted off the table?

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?

In a certain nuclear reactor, neutrons suddenly collide with deuterons, which have twice the mass of neutrons. In a head-on elastic collision with a stationary deuteron, what fraction of the initial Kinetic energy of a neutron is transferred to the deuteron?

In the figure, determine the character of the collision. The masses of the blocks, and the velocities before and after, are shown. The collision is

Three small masses are positioned as follows: 2.0 kg at (0.0 m, 0.0 m), 2.0 kg at (2.0 m, 0.0 m), and 4.0 kg at (2.0 m, 1.0 m). Determine the coordinates of the center of mass (or center of gravity) of This system.

Introduction, Measurement, Estimating

Describing Motion: Kinematics in One Dimension

Kinematics in Two Dimensions; Vectors

Dynamics: Newtons Laws of Motion

Circular Motion; Gravitation

Work and Energy

Rotational Motion

Static Equilibrium; Elasticity and Fracture

Fluids

Oscillations and Waves

Sound

Temperature and Kinetic Theory

Heat

The Laws of Thermodynamics

Electric Charge and Electric Field

Electric Potential

Electric Currents

Dc Circuits

Magnetism

Electromagnetic Induction and Faradays Law

Electromagnetic Waves

Light: Geometric Optics

The Wave Nature of Light

Optical Instruments

The Special Theory of Relativity

Early Quantum Theory and Models of the Atom

Quantum Mechanics of Atoms

Molecules and Solids

Nuclear Physics and Radioactivity

Nuclear Energy; Effects and Uses of Radiation

Elementary Particles

Astrophysics and Cosmology

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