Practice Questions
|
|
| 1. |
How
much work does a person do in pushing a box with a force of 10 N
over a distance of 4.0 m in the direction of the force? |
| (A) |
0.4 J |
| (B) |
4.0 J |
| (C) |
40 J |
| (D) |
400 J |
| (E) |
4000 J |
|
|
|
| 2. |
A
person pushes a 10 kg box at a constant velocity over a distance
of 4 m. The coefficient of kinetic friction between the box and
the floor is 0.3. How much work does the person do in pushing the
box? |
| (A) |
12 J |
| (B) |
40 J |
| (C) |
75 J |
| (D) |
120 J |
| (E) |
400 J |
|
|
|
| 3. |
How
much work does the force of gravity do in pulling a 10 kg box down
a 30º inclined plane of length 8.0 m? Note that sin 30 = cos 60
= 0.500 and cos 30 = sin 60 = 0.866. |
| (A) |
40 J |
| (B) |
69 J |
| (C) |
400 J |
| (D) |
690 J |
| (E) |
800 J |
|
|
|
| 4. |
How
much work does a person do in pushing a box with a force of 20 N
over a distance of 8.0 m in the direction of the force? |
| (A) |
1.6 J |
| (B) |
16 J |
| (C) |
160 J |
| (D) |
1600 J |
| (E) |
16000 J |
|
|
|
| 5. |
The
figure below is a force vs. displacement graph, showing the amount
of force applied to an object by three different people. Al applies
force to the object for the first 4 m of its displacement, Betty
applies force from the 4 m point to the 6 m point, and Chuck applies
force from the 6 m point to the 8 m point. Which of the three does
the most work on the object? |
|
|
| (A) |
Al |
| (B) |
Betty |
| (C) |
Chuck |
| (D) |
Al and Chuck do the same amount of work |
| (E) |
Betty and Chuck do the same amount of work |
|
|
|
| 6. |
When
a car’s speed doubles, what happens to its kinetic energy? |
| (A) |
It is quartered |
| (B) |
It is halved |
| (C) |
It is unchanged |
| (D) |
It is doubled |
| (E) |
It is quadrupled |
|
|
|
| 7. |
A
worker does 500 J of work on a 10 kg box. If the box transfers 375
J of heat to the floor through the friction between the box and
the floor, what is the velocity of the box after the work has been
done on it? |
| (A) |
5 m/s |
| (B) |
10 m/s |
| (C) |
12.5 m/s |
| (D) |
50 m/s |
| (E) |
100 m/s |
|
|
|
| 8. |
A
person on the street wants to throw an 8 kg book up to a person
leaning out of a window 5 m above street level. With what velocity
must the person throw the book so that it reaches the person in
the window? |
| (A) |
5 m/s |
| (B) |
8 m/s |
| (C) |
10 m/s |
| (D) |
40 m/s |
| (E) |
50 m/s |
|
|
|
103 W
103 W
104 W
104 W
103 W
103 W
104 W
