Question 1

Interaction partners

Accepted Answer

A)  are equal in magnitude and opposite in direction and act on the same object. 
B)  are equal in magnitude and opposite in direction and act on different objects. 
C)  appear in a free-body diagram for a given object. 
D)  always involve gravitational force as one partner. 
E)  act in the same direction on the same object. 
A)  are equal in magnitude and opposite in direction and act on the same object. 
B)  are equal in magnitude and opposite in direction and act on different objects. 
C)  appear in a free-body diagram for a given object. 
D)  always involve gravitational force as one partner. 
E)  act in the same direction on the same object.

Question 2

Two masses are connected by a cord that passes over a pulley as shown in the figure. The pulley and the cord have negligible mass and m2 (6.0 kg) moves on a horizontal surface with a coefficient of static friction of 0.5, while m1 (2.0 kg) is suspended vertically. If the masses start from rest, what is the acceleration of m2?

Accepted Answer

A)  0.0 m/s2 
B)  3.0 m/s2 
C)  1.0 m/s2 
D)  2.9 m/s2 
A)  0.0 m/s2 
B)  3.0 m/s2 
C)  1.0 m/s2 
D)  2.9 m/s2

Question 3

Causing an object to start moving on a frictional surface requires

Accepted Answer

A)  less force than is needed to keep it moving on the surface. 
B)  the same force as is needed to keep it moving on the surface. 
C)  more force than is needed to keep it moving on the surface. 
D)  a force equal to the weight of the object. 
E)  a force opposite to the normal force. 
A)  less force than is needed to keep it moving on the surface. 
B)  the same force as is needed to keep it moving on the surface. 
C)  more force than is needed to keep it moving on the surface. 
D)  a force equal to the weight of the object. 
E)  a force opposite to the normal force.

Question 4

A force of 15 N toward the WEST is applied to a 4.0 kg box. Another force of 42 N toward the EAST is also applied to the 4.0 kg box. The net force on the 4.0 kg box is

Accepted Answer

A)  57 N toward the WEST. 
B)  27 N toward the EAST. 
C)  36 N toward the WEST. 
D)  36 N toward the EAST. 
E)  17 N toward the WEST. 
A)  57 N toward the WEST. 
B)  27 N toward the EAST. 
C)  36 N toward the WEST. 
D)  36 N toward the EAST. 
E)  17 N toward the WEST.

Question 5

Five children are pushing on a snowball; each pushes with a force of magnitude 10.0 N, and each is pushing at an angle of 45° relative to his neighbor. What is the magnitude of the net push on the ball?

Accepted Answer

A)  0 N 
B)  24.1 N 
C)  27.1 N 
D)  17 N 
E)  50 N 
A)  0 N 
B)  24.1 N 
C)  27.1 N 
D)  17 N 
E)  50 N

Question 6

Two masses are connected by a string which passes over a pulley with negligible mass and friction. One mass hangs vertically and one mass slides on a 30.0 degree frictionless incline. The vertically hanging mass is 4.00 kg and the mass on the incline is 6.00 kg. The acceleration of the 4.00 kg mass is

Accepted Answer

A)  0.980 m/s2 down. 
B)  3.92 m/s2 down. 
C)  0.980 m/s2 up. 
D)  3.92 m/s2 up. 
E)  7.84 m/s2 up. 
A)  0.980 m/s2 down. 
B)  3.92 m/s2 down. 
C)  0.980 m/s2 up. 
D)  3.92 m/s2 up. 
E)  7.84 m/s2 up.

Question 7

A boy with a mass of 55 kg walks into a room and sees a girl 8.0 m in front of him who has a mass of 40 kg. What is his gravitational attraction to her?

Accepted Answer

A)  2.0 × 108 N 
B)  2.3 × 10-9 N 
C)  2.2 × 10-11 N 
D)  2.4 × 10-8 N 
E)  2.1 × 109 N 
A)  2.0 × 108 N 
B)  2.3 × 10-9 N 
C)  2.2 × 10-11 N 
D)  2.4 × 10-8 N 
E)  2.1 × 109 N

Question 8

A crate travels through a factory on a conveyor belt (without slipping) at a constant speed. The conveyer belt is inclined at some non-zero angle above the horizontal. If air resistance is negligible, what forces are active on the box?

Accepted Answer

A)  normal force, weight, static friction, kinetic friction 
B)  normal force, weight, static friction 
C)  normal force, weight, static friction, force of the conveyor belt 
D)  normal force and weight 
A)  normal force, weight, static friction, kinetic friction 
B)  normal force, weight, static friction 
C)  normal force, weight, static friction, force of the conveyor belt 
D)  normal force and weight

Question 9

Two masses are connected by a string which passes over a pulley with negligible mass and friction. One mass hangs vertically and one mass slides on a horizontal surface. The horizontal surface has a coefficient of kinetic friction of 0.200. The vertically hanging mass is 3.00 kg and the mass on the horizontal surface is 3.00 kg. The magnitude of the acceleration of the vertically hanging mass is (the initial velocity of the horizontal mass is to the right)

Accepted Answer

A)  7.16 m/s2. 
B)  5.88 m/s2. 
C)  4.02 m/s2. 
D)  3.53 m/s2. 
E)  2.00 m/s2. 
A)  7.16 m/s2. 
B)  5.88 m/s2. 
C)  4.02 m/s2. 
D)  3.53 m/s2. 
E)  2.00 m/s2.

Question 10

Two masses are being pulled up a 30.0 degree incline by a force F parallel to the incline. The acceleration down the incline is 1.00 m/s2 and the velocity is up the incline. The force is applied to a 200 kg mass, and a string connects the 200 kg mass to a 150 kg mass. The coefficient of kinetic friction is 0.200. The tension in the string is

Accepted Answer

A)  840 N. 
B)  980 N. 
C)  1,140 N. 
D)  1,530 N. 
E)  2,660 N. 
A)  840 N. 
B)  980 N. 
C)  1,140 N. 
D)  1,530 N. 
E)  2,660 N.

Question 11

Two masses are being pulled up a 30.0 degree incline by a force F parallel to the incline. The acceleration up the incline is 1.00 m/s2 and the velocity is up the incline. The force is applied to a 200 kg mass, and a string connects the 200 kg mass to a 150 kg mass. The coefficient of kinetic friction is 0.200. The tension in the string is

Accepted Answer

A)  2,660 N. 
B)  1,140 N. 
C)  980 N. 
D)  875 N. 
E)  633 N. 
A)  2,660 N. 
B)  1,140 N. 
C)  980 N. 
D)  875 N. 
E)  633 N.

Question 12

A 450 g baseball is pitched, reaching the batter with a speed of 37 m/s, and is hit such that it returns on the same line at 48 m/s. If the ball was in contact with the bat for 0.22 seconds, what was the magnitude of the average net force experienced by the ball during the time of contact?

Accepted Answer

A)  170 N 
B)  98 N 
C)  77 N 
D)  18 N 
A)  170 N 
B)  98 N 
C)  77 N 
D)  18 N

Question 13

The static friction force on an object

Accepted Answer

A)  can never be greater than the kinetic friction force on it under the same circumstances. 
B)  can never accelerate the object. 
C)  can never be greater than the normal force on it. 
D)  can never be greater than the object's weight. 
E)  None of the choices are correct. 
A)  can never be greater than the kinetic friction force on it under the same circumstances. 
B)  can never accelerate the object. 
C)  can never be greater than the normal force on it. 
D)  can never be greater than the object's weight. 
E)  None of the choices are correct.

Question 14

A tractor T is pulling a trailer M with a constant acceleration. If the forward acceleration is 1.5 m/s2 and M = 400 kg and T = 500 kg, then the force on the tractor due to the trailer is (ignore air resistance)

Accepted Answer

A)  600 N backward. 
B)  450 N backward. 
C)  200 N forward. 
D)  35 N forward. 
E)  0. 
A)  600 N backward. 
B)  450 N backward. 
C)  200 N forward. 
D)  35 N forward. 
E)  0.

Question 15

The Moon (mass 7.35 × 1022 kg) is orbiting about the Earth (mass 5.98 × 1024 kg) at a radius of 3.85 × 108 meters. The magnitude of the force of gravity on the Moon due to the Earth is (G = 6.67 × 10-11 N m2/kg2)

Accepted Answer

A)  9.20 × 1030 N. 
B)  3.20 × 1028 N. 
C)  6.70 × 1024 N. 
D)  1.98 × 1020 N. 
E)  4.10 × 1012 N. 
A)  9.20 × 1030 N. 
B)  3.20 × 1028 N. 
C)  6.70 × 1024 N. 
D)  1.98 × 1020 N. 
E)  4.10 × 1012 N.

Question 16

A box weighing 550 N slides at constant speed across a flat parking lot, under the influence of a stiff wind. The wind applies a force of 155 N parallel to the ground. What is the angle relative to the vertical of the contact force applied by the ground?

Accepted Answer

A)  75° 
B)  74° 
C)  90° 
D)  16° 
E)  15° 
A)  75° 
B)  74° 
C)  90° 
D)  16° 
E)  15°

Question 17

A 755 N box rests on a floor with a coefficient of kinetic friction of 0.600 and a coefficient of static friction of 0.800. What horizontal force is required to start the box moving?

Accepted Answer

A)  755 N 
B)  453 N 
C)  254 N 
D)  653 N 
E)  604 N 
A)  755 N 
B)  453 N 
C)  254 N 
D)  653 N 
E)  604 N

Question 18

The force that holds the nucleus together is the

Accepted Answer

A)  gravitational force. 
B)  electromagnetic force. 
C)  weak interaction. 
D)  strong nuclear force. 
A)  gravitational force. 
B)  electromagnetic force. 
C)  weak interaction. 
D)  strong nuclear force.

Question 19

A person weighs 146 pounds. The person's weight in newtons is (1 lb = 4.448 N)

Accepted Answer

A)  445 N. 
B)  500 N. 
C)  584 N. 
D)  649 N. 
A)  445 N. 
B)  500 N. 
C)  584 N. 
D)  649 N.

Question 20

You find a coin resting on your physics book cover and notice that when you open the cover, the coin slips exactly when the cover reaches 25 degrees above the horizontal. What is the coefficient of static friction between the coin and book cover?

Accepted Answer

A)  2.1 
B)  0.91 
C)  0.37 
D)  0.47 
E)  The question cannot be answered without knowing the coin's mass. 
A)  2.1 
B)  0.91 
C)  0.37 
D)  0.47 
E)  The question cannot be answered without knowing the coin's mass.

Exam 4: Force and Newtons Laws of Motion

Interaction partners

Causing an object to start moving on a frictional surface requires

A force of 15 N toward the WEST is applied to a 4.0 kg box. Another force of 42 N toward the EAST is also applied to the 4.0 kg box. The net force on the 4.0 kg box is

Five children are pushing on a snowball; each pushes with a force of magnitude 10.0 N, and each is pushing at an angle of 45° relative to his neighbor. What is the magnitude of the net push on the ball?

A boy with a mass of 55 kg walks into a room and sees a girl 8.0 m in front of him who has a mass of 40 kg. What is his gravitational attraction to her?

A crate travels through a factory on a conveyor belt (without slipping) at a constant speed. The conveyer belt is inclined at some non-zero angle above the horizontal. If air resistance is negligible, what forces are active on the box?

A 450 g baseball is pitched, reaching the batter with a speed of 37 m/s, and is hit such that it returns on the same line at 48 m/s. If the ball was in contact with the bat for 0.22 seconds, what was the magnitude of the average net force experienced by the ball during the time of contact?

The static friction force on an object

A tractor T is pulling a trailer M with a constant acceleration. If the forward acceleration is 1.5 m/s2 and M = 400 kg and T = 500 kg, then the force on the tractor due to the trailer is (ignore air resistance)

The Moon (mass 7.35 × 1022 kg) is orbiting about the Earth (mass 5.98 × 1024 kg) at a radius of 3.85 × 108 meters. The magnitude of the force of gravity on the Moon due to the Earth is (G = 6.67 × 10-11 N m2/kg2)

A box weighing 550 N slides at constant speed across a flat parking lot, under the influence of a stiff wind. The wind applies a force of 155 N parallel to the ground. What is the angle relative to the vertical of the contact force applied by the ground?

A 755 N box rests on a floor with a coefficient of kinetic friction of 0.600 and a coefficient of static friction of 0.800. What horizontal force is required to start the box moving?

The force that holds the nucleus together is the

A person weighs 146 pounds. The person's weight in newtons is (1 lb = 4.448 N)

You find a coin resting on your physics book cover and notice that when you open the cover, the coin slips exactly when the cover reaches 25 degrees above the horizontal. What is the coefficient of static friction between the coin and book cover?

Introduction

Motion Along a Line

Motion in a Plane

Circular Motion

Conservation of Energy

Linear Momentum

Torque and Angular Momentum

Fluids

Elasticity and Oscillations

Waves

Sound

Temperature and the Ideal Gas

Heat

Thermodynamics

Electric Forces and Fields

Electric Potential

Electric Current and Circuits

Magnetic Forces and Fields

Electromagnetic Induction

Alternating Current

Electromagnetic Waves

Reflection and Refraction of Light

Optical Instruments

Interference and Diffraction

Relativity

Early Quantum Physics and the Photon

Quantum Physics

Nuclear Physics

Particle Physics

Filters

A tractor T is pulling a trailer M with a constant acceleration. If the forward acceleration is 1.5 m/s² and M = 400 kg and T = 500 kg, then the force on the tractor due to the trailer is (ignore air resistance)

The Moon (mass 7.35 × 10²² kg) is orbiting about the Earth (mass 5.98 × 10²⁴ kg) at a radius of 3.85 × 10⁸ meters. The magnitude of the force of gravity on the Moon due to the Earth is (G = 6.67 × 10^-11 N m²/kg²)