ASVAB Mechanical Comprehension Practice Test 901082 Results

Your Results Global Average
Questions 5 5
Correct 0 2.88
Score 0% 58%

Review

1

Which of the following is not a type of simple machine?

58% Answer Correctly

lever

screw

gear

pulley
Solution

The six types of simple machines are the lever, wheel and axle, pulley, inclined plane, wedge, and screw.

2 A = 6 ft., the green box weighs 40 lbs., and the blue box weighs 75 lbs. What does distance B need to be for this lever to balance?
65% Answer Correctly
0 ft.
6 ft.
3.2 ft.
1.07 ft.
Solution
In order for this lever to balance, the torque acting on side A must equal the torque acting on side B. Torque is weight x distance from the fulcrum which means that the following must be true for the lever to balance:

fAdA = fBdB

For this problem, the equation becomes:

40 lbs. x 6 ft. = 75 lbs. x dB

dB = \( \frac{40 \times 6 ft⋅lb}{75 lbs.} \) = \( \frac{240 ft⋅lb}{75 lbs.} \) = 3.2 ft.

3

Connected gears of different numbers of teeth are used together to change which of the following charasteristics of the input force?

65% Answer Correctly

energy

torque

force

rotational direction
Solution

Connected gears of different numbers of teeth are used together to change the rotational speed and torque of the input force. If the smaller gear drives the larger gear, the speed of rotation will be reduced and the torque will increase. If the larger gear drives the smaller gear, the speed of rotation will increase and the torque will be reduced.

4

Which class of lever offers no mechanical advantage?

45% Answer Correctly

third

first

none of these, all levers offer mechanical advantage

second
Solution

A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers.

5

Which of the following represents how much two materials resist sliding across each other?

53% Answer Correctly

static friction

coefficient of friction

kinetic friction

normal friction
Solution

Coefficient of friction (μ) represents how much two materials resist sliding across each other.  Smooth surfaces like ice have low coefficients of friction while rough surfaces like concrete have high μ.