Question 1

Which of the following is the correct combination of dimensions for energy?

Accepted Answer

A)  MLT 
B)  LT2 /M 
C)  ML2/T2 
D)  M2L3T 
E)  ML/T2 
A)  MLT 
B)  LT2 /M 
C)  ML2/T2 
D)  M2L3T 
E)  ML/T2 C

Question 2

Power has the dimensions of:

Accepted Answer

A)  ML2/T2 
B)  MT/L2 
C)  ML/T2 
D)  ML2/T3 
E)  none of these 
A)  ML2/T2 
B)  MT/L2 
C)  ML/T2 
D)  ML2/T3 
E)  none of these D

Question 3

A baseball is hit high into the upper bleachers of left field. Over its entire flight the work done by gravity and the work done by air resistance, respectively, are:

Accepted Answer

A)  positive; positive 
B)  positive; negative 
C)  negative; positive 
D)  negative; negative 
E)  unknown since vital information is lacking 
A)  positive; positive 
B)  positive; negative 
C)  negative; positive 
D)  negative; negative 
E)  unknown since vital information is lacking D

Question 4

When a certain rubber band is stretched a distance x, it exerts a restoring force of magnitude F = Ax, where A is a constant. The work done by a person in stretching this rubber band from x = 0 to x = L is:

Accepted Answer

A)  AL2 
B)  A + 2L 
C)  A + 2L2 
D)  A/L 
E)  AL2/2 
A)  AL2 
B)  A + 2L 
C)  A + 2L2 
D)  A/L 
E)  AL2/2

Question 5

A particle moves 5 m in the positive x direction while being acted upon by a constant force   The work done on the particle by this force is:

Accepted Answer

A)  20 J 
B)  10 J 
C)  -20 J 
D)  30 J 
E)  is impossible to calculate without knowing other forces 
A)  20 J 
B)  10 J 
C)  -20 J 
D)  30 J 
E)  is impossible to calculate without knowing other forces

Question 6

A crate moves 10 m to the right on a horizontal surface as a woman pulls on it with a 10-N force. Rank the situations shown below according to the work done by her force, least to greatest.

Accepted Answer

A)  1,2,3 
B)  2,1,3 
C)  2,3,1 
D)  1,3,2 
E)  3,2,1, 
A)  1,2,3 
B)  2,1,3 
C)  2,3,1 
D)  1,3,2 
E)  3,2,1,

Question 7

An 8-N block slides down an incline. It has an initial speed of 7 m/s. The work done by the resultant force on this block is:

Accepted Answer

A)  3 J 
B)  6 J 
C)  56 J 
D)  impossible to calculate without more information 
E)  none of these 
A)  3 J 
B)  6 J 
C)  56 J 
D)  impossible to calculate without more information 
E)  none of these

Question 8

A particle starts from rest and is acted on by a net force that does work at a rate that is proportional to the time t. The speed of the particle is proportional to:

Accepted Answer

A)    
B)  t 
C)  t2 
D)    
E)  1/t 
A)    
B)  t 
C)  t2 
D)    
E)  1/t

Question 9

When a certain rubber band is stretched a distance x, it exerts a restoring force F = ax + bx2, where a and b are constants. The work done in stretching this rubber band from x = 0 to x = L is:

Accepted Answer

A)  aL2 + bLx3 
B)  aL + 2bL2 
C)  a + 2bL 
D)  bL 
E)  aL2/2 + bL3/3 
A)  aL2 + bLx3 
B)  aL + 2bL2 
C)  a + 2bL 
D)  bL 
E)  aL2/2 + bL3/3

Question 10

A 1-kg block is lifted vertically 1 m at constant speed by a boy. The work done by the boy is about:

Accepted Answer

A)  1 ft .lb 
B)  1 J 
C)  10 J 
D)  0.1 J 
E)  zero 
A)  1 ft .lb 
B)  1 J 
C)  10 J 
D)  0.1 J 
E)  zero

Question 11

At time t = 0 a 2-kg particle has a velocity in m/s of   At t = 3 s its velocity is   During this time the work done on it was:

Accepted Answer

A)  4 J 
B)  -4 J 
C)  -12 J 
D)  -40 J 
E)    
A)  4 J 
B)  -4 J 
C)  -12 J 
D)  -40 J 
E)

Question 12

The amount of work required to stop a moving object is equal to the:

Accepted Answer

A)  velocity of the object 
B)  kinetic energy of the object 
C)  mass of the object times its acceleration 
D)  mass of the object times its velocity 
E)  square of the velocity of the object 
A)  velocity of the object 
B)  kinetic energy of the object 
C)  mass of the object times its acceleration 
D)  mass of the object times its velocity 
E)  square of the velocity of the object

Question 13

A man moves the 10-g object shown in a vertical plane from position X to position Y along a circular track of radius 20 m. The process takes 0.75 min. The work done by the man is about:

Accepted Answer

A)  1 J 
B)  2 J 
C)  4 J 
D)  6 J 
E)  12 J 
A)  1 J 
B)  2 J 
C)  4 J 
D)  6 J 
E)  12 J

Question 14

A man pulls a 100-N crate up a frictionless 30$\degree$slope 5 m high as shown. Assuming that the crate moves at constant speed, the work done by the man is:

Accepted Answer

A)  -500 J 
B)  -250 J 
C)  0 
D)  250 J 
E)  500 J 
A)  -500 J 
B)  -250 J 
C)  0 
D)  250 J 
E)  500 J

Question 15

Two objects with masses, m1 and m2, have the same kinetic energy and are both moving to the right. The same constant force   is applied to the left to both masses. If m1 = 4m2, the ratio of the stopping distance of m1 to that of m2 is:

Accepted Answer

A)  1:4 
B)  4:1 
C)  1:2 
D)  2:1 
E)  1:1 
A)  1:4 
B)  4:1 
C)  1:2 
D)  2:1 
E)  1:1

Question 16

Which of the following five quantities is NOT an expression for energy? Here m is a mass, g is the acceleration due to gravity, h and d are distances, F is a force, v is a speed, a is an acceleration, P is power, and t is time.

Accepted Answer

A)  mgh 
B)  Fd 
C)  1/2mv2 
D)  ma 
E)  Pt 
A)  mgh 
B)  Fd 
C)  1/2mv2 
D)  ma 
E)  Pt

Question 17

The mechanical advantage of any machine is:

Accepted Answer

A)  the efficiency of the machine 
B)  the work done by the machine 
C)  the ratio of the work done by the machine to the work expended on it 
D)  the ratio of the force exerted by the machine to the force applied to it 
E)  the ratio of the force applied to the machine to the force exerted by it 
A)  the efficiency of the machine 
B)  the work done by the machine 
C)  the ratio of the work done by the machine to the work expended on it 
D)  the ratio of the force exerted by the machine to the force applied to it 
E)  the ratio of the force applied to the machine to the force exerted by it

Question 18

A line drive to the shortstop is caught at the same height as it was originally hit. Over its entire flight the work done by gravity and the work done by air resistance, respectively, are:

Accepted Answer

A)  zero; positive 
B)  zero; negative 
C)  positive; negative 
D)  negative; positive 
E)  negative; negative 
A)  zero; positive 
B)  zero; negative 
C)  positive; negative 
D)  negative; positive 
E)  negative; negative

Question 19

A watt per hour is a unit of:

Accepted Answer

A)  energy 
B)  power 
C)  force 
D)  acceleration 
E)  none of these 
A)  energy 
B)  power 
C)  force 
D)  acceleration 
E)  none of these

Question 20

A 0.50-kg object moves in a horizontal circular track with a radius of 2.5 m. An external force of 3.0 N, always tangent to the track, causes the object to speed up as it goes around. If it starts from rest its speed at the end of one revolution is:

Accepted Answer

A)  9.8 m/s 
B)  14 m/s 
C)  15 m/s 
D)  19 m/s 
E)  21 m/s 
A)  9.8 m/s 
B)  14 m/s 
C)  15 m/s 
D)  19 m/s 
E)  21 m/s

Exam 7: Kinetic Energy and Work

Which of the following is the correct combination of dimensions for energy?

Power has the dimensions of:

A baseball is hit high into the upper bleachers of left field. Over its entire flight the work done by gravity and the work done by air resistance, respectively, are:

When a certain rubber band is stretched a distance x, it exerts a restoring force of magnitude F = Ax, where A is a constant. The work done by a person in stretching this rubber band from x = 0 to x = L is:

A particle moves 5 m in the positive x direction while being acted upon by a constant force The work done on the particle by this force is:

A crate moves 10 m to the right on a horizontal surface as a woman pulls on it with a 10-N force. Rank the situations shown below according to the work done by her force, least to greatest.

An 8-N block slides down an incline. It has an initial speed of 7 m/s. The work done by the resultant force on this block is:

A particle starts from rest and is acted on by a net force that does work at a rate that is proportional to the time t. The speed of the particle is proportional to:

When a certain rubber band is stretched a distance x, it exerts a restoring force F = ax + bx2, where a and b are constants. The work done in stretching this rubber band from x = 0 to x = L is:

A 1-kg block is lifted vertically 1 m at constant speed by a boy. The work done by the boy is about:

At time t = 0 a 2-kg particle has a velocity in m/s of At t = 3 s its velocity is During this time the work done on it was:

The amount of work required to stop a moving object is equal to the:

A man moves the 10-g object shown in a vertical plane from position X to position Y along a circular track of radius 20 m. The process takes 0.75 min. The work done by the man is about:

A man pulls a 100-N crate up a frictionless 30 °\degree° slope 5 m high as shown. Assuming that the crate moves at constant speed, the work done by the man is:

Two objects with masses, m1 and m2, have the same kinetic energy and are both moving to the right. The same constant force is applied to the left to both masses. If m1 = 4m2, the ratio of the stopping distance of m1 to that of m2 is:

Which of the following five quantities is NOT an expression for energy? Here m is a mass, g is the acceleration due to gravity, h and d are distances, F is a force, v is a speed, a is an acceleration, P is power, and t is time.

The mechanical advantage of any machine is:

A line drive to the shortstop is caught at the same height as it was originally hit. Over its entire flight the work done by gravity and the work done by air resistance, respectively, are:

A watt per hour is a unit of:

A 0.50-kg object moves in a horizontal circular track with a radius of 2.5 m. An external force of 3.0 N, always tangent to the track, causes the object to speed up as it goes around. If it starts from rest its speed at the end of one revolution is:

Measurement

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Motion in Two and Three Dimensions

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Potential Energy and Conservation of Energy

Center of Mass and Linear Momentum

Rotation

Rolling, Torque, and Angular Momentum

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When a certain rubber band is stretched a distance x, it exerts a restoring force F = ax + bx², where a and b are constants. The work done in stretching this rubber band from x = 0 to x = L is:

Two objects with masses, m₁ and m₂, have the same kinetic energy and are both moving to the right. The same constant force is applied to the left to both masses. If m₁ = 4m₂, the ratio of the stopping distance of m₁ to that of m₂ is: