Multiple Choice
Identify the
choice that best completes the statement or answers the question.
|
|
|
1.
|
What are the base units of the SI unit of force, the newton (N)?
a. | kg·m/s | c. | kg·m/s2 | b. | kg·m2/s | d. | kg·m2/s2 |
|
|
|
2.
|
A student is pushing toward the left on a heavy box that is resting on a rough
surface. The box is not moving. What forces are acting on the box and in which
directions?
a. | force of gravity [down] and applied force
[left] | b. | force of gravity [down], normal force [up], and applied force
[left] | c. | force of gravity [down], normal force [up], force of friction
[left], and applied force [left] | d. | force of gravity [down], normal force
[up], force of friction [right], and applied force
[left] |
|
|
|
3.
|
A truck is parked on a rough hill.
Before starting the engine, the driver releases the parking brake and the car rolls downhill with
increasing speed. See the directions on the diagram. What forces are acting on the truck after the
brakes are released?
|  | | |
a. | force of friction [uphill], normal force [up], force of gravity
[toward centre of Earth] | b. | force of friction [uphill], normal
force [away from centre of Earth], force of gravity [toward centre of
Earth] | c. | force of friction [downhill], normal force [away from centre of
Earth], force of gravity [toward centre of Earth] | d. | force of friction
[downhill], normal force [away from centre of Earth], force of gravity
[toward centre of Earth] |
|
|
|
4.
|
| Two people, A and B, are dragging a
canoe across a level beach using light ropes. Person A applies a force of 40 N and person B
applies a force of 80 N. The force of friction exerted by the beach on the canoe is 100 N.
Which of the following is the correct free-body diagram for the canoe, drawn to scale? |  | | |
|
|
|
5.
|
Person A and person B are pulling on
an object unearthed at an archeological dig. They are using ropes at an angle of 30° from the forward position. Each person pulls with a force of 70 N. The
force of friction on the stone is 100 N. Which of the following is the correct free-body diagram for
the object, drawn to scale?
|  | | |
|
|
|
6.
|
Which of the following statements is always true?
a. | If an object is at rest, no forces act on it. | b. | If an object is at
rest, a net force acts on it. | c. | If an object is at rest, it has a natural
tendency to stay at rest | d. | If an object is moving, it has a natural
tendency to come to rest. |
|
|
|
7.
|
| What concept or principle explains
why, when going around a sharp curve, a motorist in a car feels as if she wants to continue moving as
shown by the dotted line? |  | | |
a. | mass | c. | the normal force | b. | inertia | d. | acceleration |
|
|
|
8.
|
Which of the following statements are correct for a motorist in a
vehicle? | I. | Inertia of a
motorist makes her feel like she is being pushed backward when the acceleration of the vehicle is in
the same direction as its velocity. | | II | Inertia of a motorist makes her feel like she is being thrown forward when the
direction of the acceleration of the vehicle is opposite to the direction of its
velocity. | | III | Inertia
of a motorist makes her feel she is being thrown inward when the direction of the velocity changes as
the vehicle accelerates around a curve. | | |
Choose your answer from the following. a. | I and II only | c. | II and III only | b. | I and III only | d. | I, II, and III |
|
|
|
9.
|
An object is given an acceleration of 2.50 m/s2 [60°] by a net force of 5.00 N [60°]. The mass of the object is:
a. | 0.500 kg | c. | 12.5 kg | b. | 2.00 kg | d. | 7.50 kg |
|
|
|
10.
|
A force of 300 N [35°] applied to a
stove on a kitchen floor produces an acceleration of 5.0 m/s2 [35°]. If the magnitude of the frictional force is 100 N, what is the
mass of the stove?
a. | 20 kg | b. | 40 kg | c. | 60 kg | d. | 80
kg |
|
|
|
11.
|
A net force of 8.0 N accelerates a 4.0-kg roast from 10 m/s [forward]
to 18 m/s [forward]. For how long was the net force applied?
a. | 1.0 s | b. | 2.0 s | c. | 4.0 s | d. | 8.0
s |
|
|
|
12.
|
An 8.0-kg oak block, X, on a
horizontal, rough oak surface is attached by a light string that passes over a light, frictionless
pulley to a hanging 4.0-kg mass, Y. The magnitude of the force of friction on block X is 24 N. What
is the tension in the string? ( = 9.81 m/s2 [down])
|  | | |
|
|
|
13.
|
Two carts, X and Y, are at rest and in contact on a level, frictionless table,
as shown. Cart X has twice the mass of cart Y but is the same distance from barrier X as cart Y is
from barrier Y. If the cocked spring on cart X is released, which of the following descriptions of
the motions of the carts is correct?  a. | Cart X will remain at rest and cart Y will hit barrier Y. | b. | Cart X will hit
barrier X before cart Y hits barrier Y. | c. | Cart X will hit barrier X after cart Y hits
barrier Y. | d. | Cart X will hit barrier X at the same time as cart Y hits barrier
Y. |
|
|
|
14.
|
An oak block is placed on a horizontal oak board and a force is applied until
the block just begins to move. In each succeeding trial, another identical block is placed on top of
the oak block to increase the mass of the system. The force needed to start the system moving each
time is recorded. Which graph best summarizes the relationship between the maximum force of static
friction,  , and the normal force,  ?
|
|
|
15.
|
A 30-kg toboggan made of birch wood is facing downhill on a well-packed snowy
slope. At a location where the slope is 25.0°, the toboggan just
begins to slide downhill. What is the coefficient of static friction for the birch toboggan on packed
snow?
|
|
|
16.
|
Which of the following statements about gravitational force,  , is
not correct? a. | Gravitational force is an attractive force only; it is never
repulsive. | b. | Gravitational force is the strongest of the fundamental forces. | c. | Gravitational forces
always exist in pairs of equal magnitude. | d. | The gravitational force between two objects
depends on their separation. |
|
|
|
17.
|
Considering gravitational and inertial mass, which statement is not
correct? Both the gravitational mass and the inertial mass of an object
a. | have the same magnitude | c. | are measured in the same
way | b. | have the same units | d. | are not affected by location |
|
|
|
18.
|
A bronze statue is placed on an equal-arm balance and requires a 12-kg mass to
balance it. When the statue is hung from a spring scale, calibrated in kilograms, the reading on
Earth is 12 kg. The equal-arm balance, spring scale, standard masses, and object are transported to
the Moon. If the force of gravity is 6.0 times greater on Earth than on the Moon, what will be the
readings on the equal-balance and on the spring scale on the Moon?
a. | equal-arm balance — 12 kg; spring scale — 12 kg | b. | equal-arm balance
— 12 kg; spring scale — 2.0 kg | c. | equal-arm balance — 12 kg; spring scale
— 72 kg | d. | equal-arm balance — 2.0 kg; spring scale — 2.0
kg |
|
|
|
19.
|
The diagram shows three locations in
the path of an imaginary planet travelling in its orbit about a star S.
At what point in its
orbit is the magnitude of the gravitational force of the star on the planet the largest? |  | | |
a. | I | b. | II | c. | III | d. | The gravitational force on the planet is the
same at all locations. |
|
|
|
20.
|
An astronaut is standing on the surface of the Moon. Assume that the Moon
suddenly shrinks to one-half its original diameter, but that its mass remains unchanged.
What
will happen to the force of gravity acting on the astronaut?
a. | It will remain unchanged. | c. | It will become four times
greater. | b. | It will become twice as great. | d. | It will become half as
great. |
|
Numeric Response
|
|
|
21.
|
A 1.25-N force is used to launch a 550-g arrow into the air. The magnitude of
the arrow’s initial acceleration is _____ m/s2. (Record your three-digit
answer on the answer sheet.)
|
|
|
22.
|
A 1.75-N force is used to launch an arrow with an initial acceleration of 3.00
m/s2 [upward]. The arrow’s mass is _____ g. (Record your three-digit
answer on the answer sheet.)
|
|
|
23.
|
On planet 518c, a 45.0-g golf ball has a weight of 0.981 N. The gravitational
field strength on planet 518c is _____ N/kg. (Record your three-digit answer on the answer
sheet.)
|
|
|
24.
|
The gravitational force exerted by the Moon on a 82.0-kg astronaut is 129.8 N.
The distance of the astronaut from the Moon’s surface is _____ km. (mMoon
= 7.3483 ´ 1022 kg, rMoon =
1.7374 ´ 106 m) (Record your three-digit answer on
the answer sheet.)
|
|
|
25.
|
Mercury has a mass of 3.30 ´ 1023 kg
and a radius of 2.44 ´ 106 m. The gravitational field
strength on the surface of Mercury is _____ N/kg. (Record your three-digit answer on the
answer sheet.)
|
Essay
|
|
|
26.
|
A 20.0-kg curling stone is released at the hog line and moves 28.35 m
[W] to sit on the button and score a point. If the coefficient of kinetic friction between
the stone and the ice is 0.00200, what was the initial speed of the stone when it was released?
(Ignore the curling of the stone because the slightly longer path of the stone is compensated for by
the sweeping of the curlers.)
|