ASVAB Mechanical Comprehension Practice Test 191215 Results

Your Results Global Average
Questions 5 5
Correct 0 3.40
Score 0% 68%

Review

1

The force amplification achieved by using a tool, mechanical device or machine system is called:

80% Answer Correctly

work

power

mechanical advantage

efficiency
Solution

Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Such a device utilizes input force and trades off forces against movement to amplify and/or change its direction.

2 What's the mechanical advantage of a wedge that's 4 inches wide and 24 inches long?
83% Answer Correctly
7.5
5.4
6
6.6
Solution

The mechanical advantage (MA) of a wedge is its length divided by its thickness:

MA = \( \frac{l}{t} \) = \( \frac{24 in.}{4 in.} \) = 6

3

The science that deals with motion and the forces that produce motion is called which of the following?

57% Answer Correctly

physics

mechanics

engineering

aeronautics
Solution

Mechanics deals with motion and the forces that produce motion.

4 If you lift a 6 lbs. rock 15 ft. from the ground, how much work have you done?
70% Answer Correctly
2 ft⋅lb
None of these is correct
0 ft⋅lb
90 ft⋅lb
Solution
Work is force times distance. In this case, the force is the weight of the rock so:
\( W = F \times d \)
\( W = 6 \times 15 \)
\( W = 90 \)
5 If the green box weighs 35 lbs. and 10 lbs. of force is applied 1 ft. from the fulcrum at the blue arrow, how far from the fulcrum would the green box need to be placed to balance the lever?
55% Answer Correctly
35 ft.
0.1 ft.
0.07 ft.
0.29 ft.
Solution

To balance this lever the torques at the green box and the blue arrow must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:

Rada = Rbdb

where a represents the green box and b the blue arrow, R is resistance (weight/force) and d is the distance from the fulcrum.

Solving for da, our missing value, and plugging in our variables yields:

da = \( \frac{R_bd_b}{R_a} \) = \( \frac{10 lbs. \times 1 ft.}{35 lbs.} \) = \( \frac{10 ft⋅lb}{35 lbs.} \) = 0.29 ft.