Practice Questions
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| 1. |
Each
of the figures below shows a particle moving with velocity v,
and with one or two forces of magnitude F acting
upon it. In which of the figures will v remain
constant? |
| (A) |
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| (B) |
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| (C) |
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| (D) |
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| (E) |
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| 2. |
In
which of the following examples is a net force of zero acting on
the object in question? |
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I. A car drives around a circular racetrack at a constant
speed
II. A person pushes on a door to hold it shut
III. A ball, rolling across a grassy field, slowly comes
to a stop
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| (A) |
I only |
| (B) |
II only |
| (C) |
III only |
| (D) |
I and II only |
| (E) |
I and III only |
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| 3. |
A
force F is acting on
an object of mass m to give it an
acceleration of a. If m is
halved and F is quadrupled,
what happens to a? |
| (A) |
It is divided by eight |
| (B) |
It is divided by two |
| (C) |
It remains unchanged |
| (D) |
It is multiplied by two |
| (E) |
It is multiplied by eight |
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| 4. |
A
force  pushes on an object of
mass 10 kg with a force of 5 N to the right. A force  pushes on the same object with a force
of 15 N to the left. What is the acceleration of the object? |
| (A) |
0.3 m/s2 to the left |
| (B) |
0.5 m/s2 to the left |
| (C) |
1 m/s2 to the left |
| (D) |
1.5 m/s2 to the left |
| (E) |
10 m/s2 to the left |
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| 5. |
In the figure above, a block is
suspended from two ropes, so that it hangs motionless in the air.
If the magnitude of  is 10.0 N, what is the
magnitude of  ? Note that sin 30 = cos
60 = 0.500, and sin 60 = cos 30 = 0.866. |
| (A) |
0.433 N |
| (B) |
0.500 N |
| (C) |
0.866 N |
| (D) |
10.0 N |
| (E) |
17.3 N |
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| 6. |
In scenario 1, a person pulls
with a force F on a string
of length 2d that is connected to
a spring scale. The other end of the spring scale is connected to
a post by a string of length d. In
scenario 2, the person pulls on the string of length 2d with
a force of F, and a second
person stands where the post was in scenario 1, and also pulls with
a force of F. If the
spring scale reads 50 N in scenario 1, what does the spring scale
read in scenario 2? |
| (A) |
50 N |
| (B) |
67 N |
| (C) |
100 N |
| (D) |
133 N |
| (E) |
150 N |
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| 7. |
In the figure above, a person
is dragging a box attached to a string along the ground. Both the
person and the box are moving to the right with a constant velocity, v.
What horizontal forces are acting on the person? |
| (A) |
The tension force in the string is pulling the person to
the left |
| (B) |
The tension force in the string is pulling the person to
the left, and the Earth is pushing the person to the right |
| (C) |
The tension force in the string is pulling the person to
the left, and the Earth is pushing the person to the left |
| (D) |
The tension force in the string is pushing the person to
the right, and the Earth is pushing the person to the right |
| (E) |
The tension force in the string is pushing the person to
the right, and the Earth is pushing the person to the left |
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| 8. |
What
is the weight of a man whose mass is 80 kg? |
| (A) |
8.1 N |
| (B) |
70.2 N |
| (C) |
80 N |
| (D) |
89.8 N |
| (E) |
784 N |
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| 9. |
A
50 kg crate rests on the floor. The coefficient of static friction
is 0.5. The force parallel to the floor needed to move the crate
is most nearly: |
| (A) |
25 N |
| (B) |
50 N |
| (C) |
125 N |
| (D) |
250 N |
| (E) |
500 N |
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| 10. |
A
person is pushing an object of mass m along
the ground with a force F.
The coefficient of kinetic friction between the object and the ground
is  . The object is accelerating, but then the
person stops pushing and the object slides to a halt. The person
then starts pushing on the object again with a force F,
but the object doesn’t budge. The maximum coefficient of static
friction between the object and the ground is  . Which of the following statements is true? |
| (A) |
 |
| (B) |
 |
| (C) |
 |
| (D) |
 |
| (E) |
The scenario described is physically impossible |
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