 |
1 | |
A moving body cannot be in equilibrium. |
|
| | A) | True |
| | B) | False |
|
2 | |
In equilibrium problems, the normal force will always equal the weight of a body. |
|
| | A) | True |
| | B) | False |
|
3 | |
According to Newton's first law of motion, every action force has an equal but opposite reaction force. |
|
| | A) | True |
| | B) | False |
|
4 | |
Action and reaction forces do not neutralize each other because they act on different objects. |
|
| | A) | True |
| | B) | False |
|
5 | |
Newton's first law of motion is also referred to as the law of inertia. |
|
| | A) | True |
| | B) | False |
|
6 | |
Under a condition of equilibrium, any one of the forces acting on an object is the equilibrant of the vector sum of all the other forces. |
|
| | A) | True |
| | B) | False |
|
7 | |
Static friction does not exist until motion is impending. |
|
| | A) | True |
| | B) | False |
|
8 | |
The maximum force of static friction is directly proportional to the weight of a body. |
|
| | A) | True |
| | B) | False |
|
9 | |
The parallel force required to move an object over a surface at constant speed is equal to the magnitude of the force of kinetic friction. |
|
| | A) | True |
| | B) | False |
|
10 | |
The higher the coefficient of friction between two surfaces, the higher will be the angle of repose for those surfaces. |
|
| | A) | True |
| | B) | False |
|
11 | |
If two vertical ropes are used to support a 20-N weight, the tension in each rope must be |
|
| | A) | 20 N |
| | B) | 40 N |
| | C) | 10 N |
| | D) | 30 N |
|
12 | |
A rope attached to a post in the ground is pulled horizontally with a force of 80 lb. The pole pulls back with a force of |
|
| | A) | 40 lb |
| | B) | 80 lb |
| | C) | 100 lb |
| | D) | 160 lb |
|
13 | |
Which of the following cannot apply for a body in translational equilibrium? |
|
| | A) | ΣFx = 0 |
| | B) | Constant speed |
| | C) | Increasing speed |
| | D) | ΣFy = 0 |
|
14 | |
Find the tension in the cable for the arrangement in Fig. 4-3. Neglect the weight of the board.
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|
| | A) | 72.1 N |
| | B) | 67.3 N |
| | C) | 45.0 N |
| | D) | 37.2 N |
|
15 | |
A 40-N block is supported by two ropes. One rope is horizontal, and the other makes an angle of 30o with the ceiling. The tension in the rope attached to the ceiling is approximately |
|
| | A) | 80 N |
| | B) | 34.6 N |
| | C) | 40 N |
| | D) | 46.2 N |
|
16 | |
A 200-lb block is at rest on a 37o inclined plane. The normal force exerted by the plane is approximately |
|
| | A) | 120 lb |
| | B) | 200 lb |
| | C) | 160 lb |
| | D) | 100 lb |
|
17 | |
A 60-lb block rests on a smooth horizontal surface. The horizontal force that just starts the block moving is found to be 30 lb. Which of the following is true for this situation? |
|
| | A) | µk = 0.5 |
| | B) | µs = 0.5 |
| | C) | µs = 0.18 |
| | D) | Fk = 30 lb |
|
18 | |
A 40-N block slides down a board with constant speed when the angle of elevation is 30o. Which of the following is not true for this situation? |
|
| | A) | tan 30o = µk |
| | B) | Fk = 20 N |
| | C) | Fk = 34.6 N |
| | D) | µk = 0.577 |
|
19 | |
It is easier to pull a sled at an angle than it is to push a sled at an angle because of a |
|
| | A) | lower normal force |
| | B) | lower weight |
| | C) | higher normal force |
| | D) | mechanical advantage |
|
20 | |
If µk = 0.1, the force required to push a 20-N sled up a 40o incline with constant speed is approximately |
|
| | A) | 26.1 N |
| | B) | 14.4 N |
| | C) | 15.3 N |
| | D) | 31.1 N |