Question 1

A girl holds a basketball in a fixed position. The work she does on the ball is

Accepted Answer

A)  dependent on the weight of the ball. 
B)  dependent on how high above the ground the ball is. 
C)  positive. 
D)  zero. 
E)  negative. 
A)  dependent on the weight of the ball. 
B)  dependent on how high above the ground the ball is. 
C)  positive. 
D)  zero. 
E)  negative. D

Question 2

A rock, tied at the end of a rope, is swirled in a vertical circle (the rock's speed changes during the motion). The work done on the rock by the tension in the rope

Accepted Answer

A)  is positive. 
B)  is zero. 
C)  is negative. 
D)  changes from positive to negative and back as the velocity of the rock changes its direction. 
E)  depends on the weight of the rock. 
A)  is positive. 
B)  is zero. 
C)  is negative. 
D)  changes from positive to negative and back as the velocity of the rock changes its direction. 
E)  depends on the weight of the rock. B

Question 3

You want to move a very heavy table across the room, but no matter how hard you push the table, it does not move. As you push harder and harder, the work done by the static friction

Accepted Answer

A)  increases. 
B)  stays the same and has a positive value. 
C)  stays the same and is zero. 
D)  stays the same and has a negative value. 
E)  decreases. 
A)  increases. 
B)  stays the same and has a positive value. 
C)  stays the same and is zero. 
D)  stays the same and has a negative value. 
E)  decreases. C

Question 4

Work has all of the following characteristics except

Accepted Answer

A)  it is a scalar. 
B)  it is a vector. 
C)  it is the cross product of two vectors. 
D)  it is the product of two scalars. 
E)  none of the above. 
A)  it is a scalar. 
B)  it is a vector. 
C)  it is the cross product of two vectors. 
D)  it is the product of two scalars. 
E)  none of the above.

Question 5

What speed should a roller coaster have at a point 30 m above the bottom of a dip if it is to barely reach the top of the next slope, which is 40 m above the bottom of the dip? Neglect friction.

Accepted Answer

A)  0 m/s 
B)  14 m/s 
C)  28 m/s 
D)  98 m/s 
E)  2.0* 102 m/s 
A)  0 m/s 
B)  14 m/s 
C)  28 m/s 
D)  98 m/s 
E)  2.0* 102 m/s

Question 6

A box is in contact with a surface that makes an angle of 30o with the horizontal. An applied horizontal force of 10.0 N allows the box to slide along the surface at a constant speed. When the box has moved 2.0 m along the surface, the work done on it by the applied force is

Accepted Answer

A)  0 J. 
B)  17.3 J. 
C)  20.0 J. 
D)  23.1 J. 
E)  40.0 J. 
A)  0 J. 
B)  17.3 J. 
C)  20.0 J. 
D)  23.1 J. 
E)  40.0 J.

Question 7

All of the following statements referring to the potential energy of a body are true except

Accepted Answer

A)  its value depends on the reference frame. 
B)  it is energy associated with the motion of the body. 
C)  it is energy associated with the position of the body. 
D)  it is negative, positive, or zero. 
E)  it decreases if positive work is done by gravity on the body. 
A)  its value depends on the reference frame. 
B)  it is energy associated with the motion of the body. 
C)  it is energy associated with the position of the body. 
D)  it is negative, positive, or zero. 
E)  it decreases if positive work is done by gravity on the body.

Question 8

Alex and Kaylee ascend a mountain on two different trails: Alex via a short, steep trail and Kaylee via a long, gentle trail. Which of the following statements is true?

Accepted Answer

A)  To compare gravitational energies one should know the height of the mountain. 
B)  To compare gravitational energies one should know how the lengths of the two trails compare. 
C)  Alex gains more gravitational energy than Kaylee. 
D)  Alex gains the same gravitational energy as Kaylee. 
E)  Alex gains less gravitational energy than Kaylee. 
A)  To compare gravitational energies one should know the height of the mountain. 
B)  To compare gravitational energies one should know how the lengths of the two trails compare. 
C)  Alex gains more gravitational energy than Kaylee. 
D)  Alex gains the same gravitational energy as Kaylee. 
E)  Alex gains less gravitational energy than Kaylee.

Question 9

A ball of mass 1.0 kg is tied to a string and allowed to revolve in a vertical circle of radius 1.5 m. If the ball's speed at the top of the trajectory is 2.3 m/s, its speed at the bottom of the trajectory is

Accepted Answer

A)  0 m/s. 
B)  2.3 m/s. 
C)  5.9 m/s. 
D)  7.7 m/s. 
E)  8.0 m/s. 
A)  0 m/s. 
B)  2.3 m/s. 
C)  5.9 m/s. 
D)  7.7 m/s. 
E)  8.0 m/s.

Question 10

It takes 100 m to stop a car initially moving at 25.0 m/s. The distance required to stop the same car moving at 50.0 m/s under the same conditions is

Accepted Answer

A)  25.0 m. 
B)  50.0 m. 
C)  100 m. 
D)  200 m. 
E)  400 m. 
A)  25.0 m. 
B)  50.0 m. 
C)  100 m. 
D)  200 m. 
E)  400 m.

Question 11

In a television tube, an electron (mass 9.1 * 10-31 kg) starting from rest experiences a force of 4.8 *10-15 N over a distance of 45 cm. Ignoring relativistic effects, the final speed of the electron is

Accepted Answer

A)  4.7 *1015 m/s. 
B)  2.3 * 107 m/s. 
C)  4.9* 107 m/s. 
D)  6.9 * 107 m/s. 
E)  4.7 * 10-15 m/s. 
A)  4.7 *1015 m/s. 
B)  2.3 * 107 m/s. 
C)  4.9* 107 m/s. 
D)  6.9 * 107 m/s. 
E)  4.7 * 10-15 m/s.

Question 12

Two stones, A and B, are thrown from a balcony with the same initial speed: stone A horizontally, and stone B at 30o above the horizontal. Just before their impact with the ground, in the absence of air resistance

Accepted Answer

A)  the velocity of A is larger than the velocity of B. 
B)  the velocity of A is the same as the velocity of B. 
C)  the velocity of A is smaller than the velocity of B. 
D)  both velocities are zero. 
A)  the velocity of A is larger than the velocity of B. 
B)  the velocity of A is the same as the velocity of B. 
C)  the velocity of A is smaller than the velocity of B. 
D)  both velocities are zero.

Question 13

All of the following statements referring to the kinetic energy of a body are true except

Accepted Answer

A)  its value depends on reference frame. 
B)  it is energy associated with the motion of the body. 
C)  it is energy associated with the position of the body. 
D)  it is positive or zero. 
E)  it increases if work is done on the body. 
A)  its value depends on reference frame. 
B)  it is energy associated with the motion of the body. 
C)  it is energy associated with the position of the body. 
D)  it is positive or zero. 
E)  it increases if work is done on the body.

Question 14

A girl runs up a flight of stairs at a constant speed v, and the gain in her potential gravitational energy is U. When she runs up the same stairs at half that speed, the gain in her potential gravitational energy is

Accepted Answer

A)  0. 
B)  U/4. 
C)  U/2. 
D)  U. 
E)  2U. 
A)  0. 
B)  U/4. 
C)  U/2. 
D)  U. 
E)  2U.

Question 15

A 3.0-kg box is in contact with a surface that makes an angle of 30o with the horizontal. When the box has moved 2.0 m along the surface, the work done on it by gravity is

Accepted Answer

A)  0 J. 
B)  3.0 J. 
C)  5.2 J. 
D)  6.0 J. 
E)  6.9 J. 
A)  0 J. 
B)  3.0 J. 
C)  5.2 J. 
D)  6.0 J. 
E)  6.9 J.

Question 16

A force of variable magnitude acting on a toy car is represented in a F vs. x graph. The work done by this force on the toy car is

Accepted Answer

A)  the value of F multiplied by the value of x at a certain instant. 
B)  the area bounded by the curve and the F axis. 
C)  the slope of the curve. 
D)  the area bounded by the curve and the x axis. 
E)  the value of F divided by the value of x at a certain instant. 
A)  the value of F multiplied by the value of x at a certain instant. 
B)  the area bounded by the curve and the F axis. 
C)  the slope of the curve. 
D)  the area bounded by the curve and the x axis. 
E)  the value of F divided by the value of x at a certain instant.

Question 17

A 600-kg elevator is pulled upward with a constant force of 6.0 kN for a distance of 30.0 m. The net work done by the elevator is

Accepted Answer

A)  -3.6 * 105 J. 
B)  -3.6 *103 J. 
C)  0 J. 
D)  3.6 * 103 J. 
E)  3.6 * 105 J. 
A)  -3.6 * 105 J. 
B)  -3.6 *103 J. 
C)  0 J. 
D)  3.6 * 103 J. 
E)  3.6 * 105 J.

Question 18

An 11.0-g bullet traveling at 700 m/s strikes a block of wood fixed in place, penetrates, and travels a distance of 6.0 cm in the block before it stops. The average force exerted by the wooden block on the bullet was

Accepted Answer

A)  6.4 * 101 N. 
B)  6.4 * 102 N. 
C)  4.5* 104 N. 
D)  4.5 * 105 N. 
E)  4.5 * 106 N. 
A)  6.4 * 101 N. 
B)  6.4 * 102 N. 
C)  4.5* 104 N. 
D)  4.5 * 105 N. 
E)  4.5 * 106 N.

Question 19

A container of water is lifted vertically 2.0 m and then returned to its original position. If the container's weight is 30 N, the work done during the process is

Accepted Answer

A)  0 J. 
B)  7.5 J. 
C)  15 J. 
D)  60 J. 
E)  1.2 *102 J. 
A)  0 J. 
B)  7.5 J. 
C)  15 J. 
D)  60 J. 
E)  1.2 *102 J.

Question 20

A 1.0-kg ball is moving at 2.0 m/s, while a 4.0-kg mass is moving at 1.0 m/s. Both are brought to rest by the same constant braking force. The ball that travels the greater distance before stopping is

Accepted Answer

A)  the 1.0-kg ball. 
B)  the 4.0-kg ball. 
C)  Both the 1.0-kg and the 4.0-kg ball travel the same distance. 
D)  More information is needed to work out the answer. 
A)  the 1.0-kg ball. 
B)  the 4.0-kg ball. 
C)  Both the 1.0-kg and the 4.0-kg ball travel the same distance. 
D)  More information is needed to work out the answer.

Exam 7: Work and Energy

A girl holds a basketball in a fixed position. The work she does on the ball is

A rock, tied at the end of a rope, is swirled in a vertical circle (the rock's speed changes during the motion). The work done on the rock by the tension in the rope

You want to move a very heavy table across the room, but no matter how hard you push the table, it does not move. As you push harder and harder, the work done by the static friction

Work has all of the following characteristics except

What speed should a roller coaster have at a point 30 m above the bottom of a dip if it is to barely reach the top of the next slope, which is 40 m above the bottom of the dip? Neglect friction.

A box is in contact with a surface that makes an angle of 30o with the horizontal. An applied horizontal force of 10.0 N allows the box to slide along the surface at a constant speed. When the box has moved 2.0 m along the surface, the work done on it by the applied force is

All of the following statements referring to the potential energy of a body are true except

Alex and Kaylee ascend a mountain on two different trails: Alex via a short, steep trail and Kaylee via a long, gentle trail. Which of the following statements is true?

A ball of mass 1.0 kg is tied to a string and allowed to revolve in a vertical circle of radius 1.5 m. If the ball's speed at the top of the trajectory is 2.3 m/s, its speed at the bottom of the trajectory is

It takes 100 m to stop a car initially moving at 25.0 m/s. The distance required to stop the same car moving at 50.0 m/s under the same conditions is

In a television tube, an electron (mass 9.1 * 10-31 kg) starting from rest experiences a force of 4.8 *10-15 N over a distance of 45 cm. Ignoring relativistic effects, the final speed of the electron is

Two stones, A and B, are thrown from a balcony with the same initial speed: stone A horizontally, and stone B at 30o above the horizontal. Just before their impact with the ground, in the absence of air resistance

All of the following statements referring to the kinetic energy of a body are true except

A girl runs up a flight of stairs at a constant speed v, and the gain in her potential gravitational energy is U. When she runs up the same stairs at half that speed, the gain in her potential gravitational energy is

A 3.0-kg box is in contact with a surface that makes an angle of 30o with the horizontal. When the box has moved 2.0 m along the surface, the work done on it by gravity is

A force of variable magnitude acting on a toy car is represented in a F vs. x graph. The work done by this force on the toy car is

A 600-kg elevator is pulled upward with a constant force of 6.0 kN for a distance of 30.0 m. The net work done by the elevator is

An 11.0-g bullet traveling at 700 m/s strikes a block of wood fixed in place, penetrates, and travels a distance of 6.0 cm in the block before it stops. The average force exerted by the wooden block on the bullet was

A container of water is lifted vertically 2.0 m and then returned to its original position. If the container's weight is 30 N, the work done during the process is

A 1.0-kg ball is moving at 2.0 m/s, while a 4.0-kg mass is moving at 1.0 m/s. Both are brought to rest by the same constant braking force. The ball that travels the greater distance before stopping is

Space, Time, and Mass

Motion Along a Straight Line

Vectors

Motion in Two and Three Dimensions

Newtons Laws of Motion

Further Applications of Newtons Laws

Conservation of Energy

Gravitation

Systems of Particles

Collisions

Rotation of a Rigid Body

Dynamics of a Rigid Body

Statics and Elasticity

Oscillations

Waves

Sound

Fluid Mechanics

The Ideal Gas

Heat

Thermodynamics

Electric Force and the Electric Charge

The Electric Field

Gauss Law

Electrostatic Potential and Energy

Capacitors and Dielectrics

Currents and Ohms Law

Direct Current Circuits

Magnetic Force and Field

Charges and Currents in Magnetic Fields

Electromagnetic Induction

Alternating Current Circuits

Electromagnetic Waves

Reflection, Refraction, and Optics

Interference and Diffraction

The Theory of Special Relativity

Quanta of Light

Spectral Lines, Bohrs Theory, and Quantum Mechanics

Quantum Structure of Atoms, Molecules, and Solids

Nuclei

Elementary Particles and Cosmology

Filters

A box is in contact with a surface that makes an angle of 30^o with the horizontal. An applied horizontal force of 10.0 N allows the box to slide along the surface at a constant speed. When the box has moved 2.0 m along the surface, the work done on it by the applied force is

In a television tube, an electron (mass 9.1 * 10^-31 kg) starting from rest experiences a force of 4.8 *10^-15N over a distance of 45 cm. Ignoring relativistic effects, the final speed of the electron is

Two stones, A and B, are thrown from a balcony with the same initial speed: stone A horizontally, and stone B at 30^o above the horizontal. Just before their impact with the ground, in the absence of air resistance

A 3.0-kg box is in contact with a surface that makes an angle of 30^o with the horizontal. When the box has moved 2.0 m along the surface, the work done on it by gravity is