Test Bank for Physics Principles with Applications ((6))

Chapter 6: Work and Energy



10) On a plot of Force versus position (F vs. x), what represents the work done by the force F?
A) the slope of the curve
B) the length of the curve
C) the area under the curve
D) the product of the maximum force times the maximum x
Answer: C
Diff: 1 Page Ref: Sec. 6.2


11) The quantity 1/2 mv2 is
A) the kinetic energy of the object.
B) the potential energy of the object.
C) the work done on the object by the force.
D) the power supplied to the object by the force.
Answer: A
Diff: 1 Page Ref: Sec. 6.3


12) If the net work done on an object is positive, then the object's kinetic energy
A) decreases.
B) remains the same.
C) increases.
D) is zero.
Answer: C
Diff: 1 Page Ref: Sec. 6.3


13) If the net work done on an object is negative, then the object's kinetic energy
A) decreases.
B) remains the same.
C) increases.
D) is zero.
Answer: A
Diff: 1 Page Ref: Sec. 6.3


14) If the net work done on an object is zero, then the object's kinetic energy
A) decreases.
B) remains the same.
C) increases.
D) is zero.
Answer: B
Diff: 1 Page Ref: Sec. 6.3




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15) A truck weighs twice as much as a car, and is moving at twice the speed of the car. Which
statement is true about the truck's kinetic energy compared to that of the car?
A) All that can be said is that the truck has more kinetic energy.
B) The truck has twice the kinetic energy of the car.
C) The truck has 4 times the kinetic energy of the car.
D) The truck has 8 times the kinetic energy of the car.
Answer: D
Diff: 1 Page Ref: Sec. 6.3


16) Car J moves twice as fast as car K, and car J has half the mass of car K. The kinetic energy of
car J, compared to car K is
A) the same.
B) 2 to 1.
C) 4 to 1.
D) 1 to 2.
Answer: B
Diff: 2 Page Ref: Sec. 6.3


17) An object hits a wall and bounces back with half of its original speed. What is the ratio of the
final kinetic energy to the initial kinetic energy?
A) 1/2
B) 1/4
C) 2
D) 4
Answer: B
Diff: 2 Page Ref: Sec. 6.3


18) A brick is moving at a speed of 3 m/s and a pebble is moving at a speed of 5 m/s. If both
objects have the same kinetic energy, what is the ratio of the brick's mass to the rock's mass?
A) 25 to 9
B) 5 to 3
C) 12.5 to 4.5
D) 3 to 5
Answer: A
Diff: 2 Page Ref: Sec. 6.3




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,Chapter 6: Work and Energy



19) A 4.0-kg mass is moving with speed 2.0 m/s. A 1.0-kg mass is moving with speed 4.0 m/s.
Both objects encounter the same constant braking force, and are brought to rest. Which object
travels the greater distance before stopping?
A) the 4.0-kg mass
B) the 1.0-kg mass
C) Both travel the same distance.
D) cannot be determined from the information given
Answer: C
Diff: 2 Page Ref: Sec. 6.3


20) You slam on the brakes of your car in a panic, and skid a certain distance on a straight, level
road. If you had been traveling twice as fast, what distance would the car have skidded, under
the same conditions?
A) It would have skidded 4 times farther.
B) It would have skidded twice as far.
C) It would have skidded 1.4 times farther.
D) It is impossible to tell from the information given.
Answer: A
Diff: 2 Page Ref: Sec. 6.3


21) A planet of constant mass orbits the Sun in an elliptical orbit. Neglecting any friction effects,
what happens to the planet's kinetic energy?
A) It remains constant.
B) It increases continually.
C) It decreases continually.
D) It increases when the planet approaches the Sun, and decreases when it moves farther
away.
Answer: D
Diff: 2 Page Ref: Sec. 6.3


22) State the work-energy principle.
Answer: The net work done on an object is equal to the change in the object's kinetic energy.
Diff: 1 Page Ref: Sec. 6.3


23) The quantity mgy is
A) the kinetic energy of the object.
B) the gravitational potential energy of the object.
C) the work done on the object by the force.
D) the power supplied to the object by the force.
Answer: B
Diff: 1 Page Ref: Sec. 6.4-6.5




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24) The quantity 1/2 kx2 is
A) the kinetic energy of the object.
B) the elastic potential energy of the object.
C) the work done on the object by the force.
D) the power supplied to the object by the force.
Answer: B
Diff: 1 Page Ref: Sec. 6.4-6.5


25) Is it possible for a system to have negative potential energy?
A) Yes, as long as the total energy is positive.
B) Yes, since the choice of the zero of potential energy is arbitrary.
C) No, because the kinetic energy of a system must equal its potential energy.
D) No, because this would have no physical meaning.
Answer: B
Diff: 1 Page Ref: Sec. 6.4-6.5


26) An object is released from rest a height h above the ground. A second object with four times
the mass of the first if released from the same height. The potential energy of the second object
compared to the first is
A) one-fourth as much.
B) one-half as much.
C) twice as much.
D) four times as much.
Answer: D
Diff: 1 Page Ref: Sec. 6.4-6.5


27) A 0.200-kg mass attached to the end of a spring causes it to stretch 5.0 cm. If another 0.200-kg
mass is added to the spring, the potential energy of the spring will be
A) the same.
B) twice as much.
C) 3 times as much.
D) 4 times as much.
Answer: D
Diff: 2 Page Ref: Sec. 6.4-6.5


28) The total mechanical energy of a system
A) is equally divided between kinetic energy and potential energy.
B) is either all kinetic energy or all potential energy, at any one instant.
C) can never be negative.
D) is constant, only if conservative forces act.
Answer: D
Diff: 1 Page Ref: Sec. 6.6-6.7


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