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Chapter 5 and 6 Practice MC Questions for Test AP B
Answers are starred
2014
1.
A concrete block is pulled 7.0 m across a frictionless surface by means of a rope.
The tension in the rope is 40 N; and the net work done on the block is 247 J.
What angle does the rope make with the horizontal?
*A. 28°
B.
41°
C.
47°
D.
62°
E.
88°
2.
A.
B.
*C.
D.
E.
Which one of the following statements concerning kinetic energy is true?
It can be measured in watts.
It is always equal to the potential energy.
It is always positive.
It is a quantitative measure of inertia.
It is directly proportional to velocity.
3.
How much energy is dissipated in braking a 1000-kg car to a stop from an initial
speed of 20 m/s?
A.
20 000 J
*B. 200 000 J
C.
400 000 J
D.
800 000 J
E.
10 000 J
4. In which one of the following systems is there a decrease in gravitational potential
energy?
A.
a boy stretches a horizontal spring
*B. a girl jumps down from a bed
C.
a crate rests at the bottom of an inclined plane
D.
a car ascends a steep hill
E.
water is forced upward through a pipe
5.
A 1500-kg elevator moves upward with constant speed through a vertical distance
of 25 m. How much work was done by the tension in the cable?
A.
990 J
B.
8100 J
C.
140 000 J
*D. 370 000 J
E.
430 000 J
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6. Two balls of equal size are dropped from the same height from the roof of a
building. One ball has twice the mass of the other. When the balls reach the ground, how
do the kinetic energies of the two balls compare?
A.
The lighter one has one fourth as much kinetic energy as the other does.
*B. The lighter one has one half as much kinetic energy as the other does.
C.
The lighter one has the same kinetic energy as the other does.
D.
The lighter one has twice as much kinetic energy as the other does.
E.
The lighter one has four times as much kinetic energy as the other does.
7.
The initial velocity of a 4.0-kg box is 11 m/s, due west. After the box slides 4.0 m
horizontally, its speed is 1.5 m/s. Determine the magnitude and the direction of the nonconservative force acting on the box as it slides.
A.
42 N, due west
B.
120 N, due east
C.
31 N, due east
*D. 59 N, due east
E.
83 N, due west
8.
A rock is whirled on the end of a string in a horizontal circle of radius R with a
constant period T. If the radius of the circle is reduced to R/2, while the period remains T,
what happens to the centripetal acceleration of the rock?
A.
It remains the same.
B.
It increases by a factor of 2.
C.
It increases by a factor of 4.
*D. It decreases by a factor of 2.
E.
It decreases by a factor of 4.
9.
A 0.25-kg ball attached to a string is rotating in a horizontal circle of radius 0.5 m.
If the ball revolves twice every second, what is the tension in the string?
A.
2N
B.
5N
C.
7N
D.
10 N
*E. 20 N
10.
Sara puts a box into the trunk of her car. Later, she drives around an unbanked
curve that has a radius of 48 m. The speed of the car on the curve is 16 m/s, but the box
remains stationary relative to the floor of the trunk. Determine the coefficient of static
friction for the box on the floor of the trunk.
A.
0.42
*B. 0.54
C.
0.17
D.
0.33
E.
This cannot be determined without knowing the mass of the box.
2
11.
A.
B.
C.
D.
*E.
Which force is responsible for holding a car in a frictionless banked curve?
the reaction force to the car's weight
the vertical component of the car's weight
the vertical component of the normal force
the horizontal component of the car's weight
the horizontal component of the normal force
12.
A.
*B.
C.
D.
E.
Which force is responsible for holding a car in an unbanked curve?
the car's weight
the force of static friction
the reaction force to the car's weight
the vertical component of the normal force
the horizontal component of the normal force
13. A satellite in orbit around the earth has a period of one hour. An identical satellite is
placed in an orbit having a radius that is nine times larger than that of the first satellite.
What is the period of the second satellite?
A) 0.04 h
B) 3 h
C) 4 h
D) 9 h
*E) 27 h
14. A plane is traveling at 200 m/s following the arc of a vertical circle of radius R. At
the top of its path, the passengers experience “weightlessness” which means Fn is zero.
To one significant figure, what is the value of R?
A) 200 m
B) 1000 m
C) 2000 m
*D) 4000 m
E) 40 000 m
15. An escalator is 30.0 meters long and slants at 30.0° relative to the horizontal. If it
moves at 1.00 m/s, at what rate does it do work in lifting a 50.0-kg woman from the
bottom to the top of the escalator? (Hint, use velocity to find the time it takes to move the
30 meters).
A) 49.3 W
B) 98.0 W
*C) 245 W
D) 292 W
E) 495 W
16. A physics student shoves a 0.50-kg block from the bottom of a frictionless 30.0°
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inclined plane. The student performs 4.0 J of work and the block slides a distance s along
the incline before it stops. Determine the value of s. ( Hint: what is the force down the
slope here?)
A) 8.0 cm
B) 16 cm
C) 82 cm
*D) 160 cm
E) 330 cm
17.
A 2400-kg satellite is in a circular orbit around a planet. The satellite travels with
a constant speed of 6.67  103 m/s.
The radius of the circular orbit is 8.92  106 m.
At the instant shown in the figure, which arrow indicates the direction of the net force on
the satellite?
Answer is A.
18. A dam is used to block the passage of a river and to generate electricity.
Approximately 5.73  104 kg of water fall each second through a height of 19.6 m. If 85
% of the gravitational potential energy of the water were converted to electrical energy,
how much power would be generated?
*A) 9.36  106 W
B) 1.52  107 W
C) 1.08 x 107 W
D) 1.35 x 108 W
E) 4.68 x 106 W
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19. The graph shows the force component along the displacement as a function of the
magnitude of the displacement. Determine the work done by the force during the interval
from 2 to 10 m.
A.
*B.
C.
D.
E.
140 J
180 J
270
450 J
560 J
20.
The force component acting on an object along the displacement varies with the
displacement d as shown in the graph. Determine the work done on the object as it travels
from d = 1.0 to 10 m.
9
8
7
F COS(THETA) 6
5
Newtons
4
3
2
1
0
1
2
3
4
5
6
7
8
9
10
D -Meters
A.
*B.
C.
D.
E.
approximately 18 J
approximately 37 J
approximately 72 J
approximately 25 J
approximately 81 J
5