MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) If you push for an hour against a stationary wall, you do no work
A) on the wall. B) at all. C) both of these. D) none of these.
2) If you push an object just as far while applying twice the force you do
A) twice as much work.
B) four times as much work.
C) the same amount of work.
3) If you do work on an object in half the usual time, your power output is
A) half the usual power output.
B) the usual power output.
C) twice the usual power output.
4) Do 100 J of work in 50 s and your power output is
A) 1/4 W.
B) 1/2 W.
C) 2 W.
D) 4 W.
E) more than 4 W.
5) When an object is lifted 10 meters, it gains a certain amount of potential energy. If the same object is lifted 20 meters, its potential energy gain is
A) less.
B) the same.
C) twice as much.
D) four times as much.
E) more than 4 times as much.
6) Bullets are fired from an airplane in the forward direction of motion. The momentum of the airplane will be
A) decreased. B) unchanged. C) increased.
7) A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will ideally have a kinetic energy of
A) less than 40 J. B) more than 40 J. C) 40 J.
8) A hydraulic press, like a simple lever, properly arranged is capable of multiplying energy input.
A) sometimes true B) always false C) always true
9) Which requires more work: lifting a 50-kg sack vertically 2 meters or lifting a 25-kg sack vertically 4 meters?
A) lifting the 50-kg sack.
B) lifting the 25-kg sack.
C) both require the same amount of work.
10) A TV set is pushed a distance of 2 m with a force of 20 N that is in the same direction as the set moves. How much work is done on the set?
A) 2 J. B) 10 J. C) 20 J. D) 40 J. E) 80 J.
11) A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has
A) 4 times the KE. B) 8 times the KE.
C) 12 times the KE. D) 16 times the KE.
12) An ungloved fist will do more damage to a jaw than a gloved fist. The reason for this is that the ungloved fist
A) delivers a larger impulse to the jaw. B) exerts a larger force on the jaw.
C) has less air resistance on it. D) none of these.
13) A diver who weighs 500 N steps off a diving board that is 10 m above the water. The diver hits the water with kinetic energy of
A) 10 J.
B) 500 J.
C) 510 J.
D) 5000 J.
E) more than 5000 J.
14) A jack system will increase the potential energy of a heavy load by no more than 1000 J with a work input of 2000 J. The efficiency of the jack system is no more than
A) 10 %.
B) 20 %.
C) 50 %.
D) 80 %.
E) not enough information given.
15) How many Joules of energy are in one kilowatt-hour?
A) 1
B) 60
C) 60,000
D) 3.6 million
E) none of these.
16) A coin and a ring roll down an incline starting at the same time. The one to reach the bottom first will be the
A) ring.
B) coin.
C) both reach the bottom at the same time.
17) A torque acting on an object tends to produce
A) equilibrium.
B) rotation.
C) linear motion.
D) velocity.
E) a center of gravity.
18) The long, heavy tail of a spider monkey enables the monkey to easily vary its
A) weight.
B) momentum.
C) inertia.
D) center of gravity.
E) none of these.
19) The famous Leaning Tower of Pisa doesn't topple over because its center of gravity is
A) above a place of support.
B) relatively low for such a tall building.
C) stabilized by its structure.
D) displaced from its center.
E) in the same place as its center of mass.
20) Centrifugal forces are an apparent reality to observers in a reference frame that is
A) moving at constant velocity.
B) an inertial reference frame.
C) at rest.
D) rotating.
E) none of these.
21) When a twirling ice skater brings her arms inward, her rotational speed
A) increases. B) decreases. C) remains the same.
22) A huge rotating cloud of particles in space gravitate together to form an increasingly dense ball. As it shrinks in size the cloud
A) rotates faster.
B) rotates slower.
C) rotates at the same speed.
23) Suppose you put very large-diameter tires on your car. Then, your speedometer will show a speed that is
A) higher than it is actually. B) lower than it is actually.
24) A ring, a disk, and a solid sphere begin rolling down a hill together. The one to reach the bottom first is the
A) ring.
B) disk.
C) sphere.
D) they all reach the bottom at the same time.
E) not enough information is given.
1) Answer: A
2) Answer: A
3) Answer: C
4) Answer: C
5) Answer: C
6) Answer: A
7) Answer: C
8) Answer: B
9) Answer: C
10) Answer: D
11) Answer: D
12) Answer: B
13) Answer: D
14) Answer: C
15) Answer: D
16) Answer: B
17) Answer: B
18) Answer: D
19) Answer: A
20) Answer: D
21) Answer: A
22) Answer: A
23) Answer: B
24) Answer: C