ASVAB Mechanical Comprehension Practice Test 872034 Results

Your Results Global Average
Questions 5 5
Correct 0 3.06
Score 0% 61%

Review

1

Gear ratio indicates which of the following about two connected gears?

59% Answer Correctly

power conversion

work done

efficiency

mechanical advantage
Solution

The mechanical advantage (amount of change in speed or torque) of connected gears is proportional to the number of teeth each gear has. Called gear ratio, it's the ratio of the number of teeth on the larger gear to the number of teeth on the smaller gear.  For example, a gear with 12 teeth connected to a gear with 9 teeth would have a gear ratio of 4:3.

2

The principle of moments defines equilibrium in terms of:

53% Answer Correctly

power

speed

torque

energy
Solution

According to the principle of moments, you can maintain equilibrium if the moments (forces) tending to clockwise rotation are equal to the moments tending to counterclockwise rotation. Another name for these moments of force is torque.

3 If you lift a 30 lbs. rock 19 ft. from the ground, how much work have you done?
70% Answer Correctly
570 ft⋅lb
1140 ft⋅lb
11 ft⋅lb
0 ft⋅lb
Solution
Work is force times distance. In this case, the force is the weight of the rock so:
\( W = F \times d \)
\( W = 30 \times 19 \)
\( W = 570 \)
4

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

53% Answer Correctly

coefficient of friction

kinetic friction

normal friction

static 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.

5 If the green arrow in this diagram represents 200 ft⋅lb of work, how far will the box move if it weighs 100 pounds?
72% Answer Correctly
200 ft.
8 ft.
25 ft.
2 ft.
Solution
The Law of Work states that the work put into a machine is equal to the work received from the machine under ideal conditions. In equation form, that's:

Win = Wout
Feffort x deffort = Fresistance x dresistance

In this problem, the effort work is 200 ft⋅lb and the resistance force is 100 lbs. and we need to calculate the resistance distance:

Win = Fresistance x dresistance
200 ft⋅lb = 100 lbs. x dresistance
dresistance = \( \frac{200ft⋅lb}{100 lbs.} \) = 2 ft.