ASVAB Mechanical Comprehension Practice Test 674862 Results

Your Results Global Average
Questions 5 5
Correct 0 3.18
Score 0% 64%

Review

1 A = 8 ft., the green box weighs 45 lbs., and the blue box weighs 60 lbs. What does distance B need to be for this lever to balance?
65% Answer Correctly
6 ft.
7 ft.
480 ft.
360 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:

45 lbs. x 8 ft. = 60 lbs. x dB

dB = \( \frac{45 \times 8 ft⋅lb}{60 lbs.} \) = \( \frac{360 ft⋅lb}{60 lbs.} \) = 6 ft.

2

Which of the following is not a modulus of elasticity?

47% Answer Correctly

stretch modulus

bulk modulus

shear modulus

stress modulus
Solution

The modulus of elasticity measures how much a material or structure will deflect under stress. Stretch modulus is longitudinal stretch (like stretching raw bread dough), shear modulus is longitudinal deflection (like the horizontal displacement of a stack of magzines when a heavy object is placed upon them), and bulk modulus is compression of volume (like the compression of a loaf of bread under a heavy can at the bottom of a grocery bag).

3

What is work?

60% Answer Correctly

The potential for exertion

Force per unit distance

The movement of an object by a force

Force per unit time
Solution

Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done. By definition, work is the displacement of an object resulting from applied force.

4

Which of the following surfaces would have the lowest coefficient of friction?

86% Answer Correctly

concrete

ice

tile

leather
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

Which of the following statements about drag is false?

58% Answer Correctly

drag occurs during movement through a fluid

the amount of drag depends on the shape of an object

slower objects experience more drag than faster objects

the amount of drag depends on the speed of an object
Solution

Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area.