ASVAB Mechanical Comprehension Practice Test 527837 Results

Your Results Global Average
Questions 5 5
Correct 0 2.91
Score 0% 58%

Review

1 A mass of air has a pressure of 9.0 psi and a volume of 45 ft.3. If the air is compressed to a new volume of 40 ft.3, what is the new pressure?
56% Answer Correctly
13.1 psi
15.2 psi
10.1 psi
5.1 psi
Solution

According to Boyle's Law, pressure and volume are inversely proportional:

\( \frac{P_1}{P_2} \) = \( \frac{V_2}{V_1} \)

In this problem, V2 = 40 ft.3, V1 = 45 ft.3 and P1 = 9.0 psi. Solving for P2:

P2 = \( \frac{P_1}{\frac{V_2}{V_1}} \) = \( \frac{9.0 psi}{\frac{40 ft.^3}{45 ft.^3}} \) = 10.1 psi

2 If input effort is 700 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 2?
79% Answer Correctly
1400 ft⋅lb
0ft⋅lb
350ft⋅lb
700ft⋅lb
Solution
Mechanical advantage is the ratio of output force to input force and tells us by how many times a machine multiplies input effort. So, a machine with a mechanical advantage of 2 will multiply an input effort of 700 ft⋅lb by 2 to produce an output effort of 1400 ft⋅lb.
3

The principle of moments defines equilibrium in terms of:

53% Answer Correctly

power

energy

speed

torque
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.

4 The green box weighs 40 lbs. and a 45 lbs. weight is placed 7 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?
57% Answer Correctly
1.97 ft.
7.88 ft.
5 ft.
31.5 ft.
Solution

To balance this lever the torques on each side of the fulcrum must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:

Rada = Rbdb

where a represents the left side of the fulcrum and b the right, R is resistance (weight) and d is the distance from the fulcrum.

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

da = \( \frac{R_bd_b}{R_a} \) = \( \frac{45 lbs. \times 7 ft.}{40 lbs.} \) = \( \frac{315 ft⋅lb}{40 lbs.} \) = 7.88 ft.

5

Which of the following is not a type of structural load?

49% Answer Correctly

live load

dead load

wind load

occupancy load
Solution

Dead load is the weight of the building and materials, live load is additional weight due to occupancy or use, snow load is the weight of accumulated snow on a structure and wind load is the force of wind pressures against structure surfaces.