ASVAB Mechanical Comprehension Practice Test 458485 Results

Your Results Global Average
Questions 5 5
Correct 0 3.51
Score 0% 70%

Review

1

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

58% Answer Correctly

screw

lever

gear

pulley
Solution

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

2 If you lift a 7 lbs. rock 49 ft. from the ground, how much work have you done?
70% Answer Correctly
686 ft⋅lb
343 ft⋅lb
-42 ft⋅lb
0 ft⋅lb
Solution
Work is force times distance. In this case, the force is the weight of the rock so:
\( W = F \times d \)
\( W = 7 \times 49 \)
\( W = 343 \)
3

Which of these is the formula for force?

76% Answer Correctly

F = ma

F = am2

F = a/m

F = m/a
Solution

Newton's Second Law of Motion states that "The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object." This Law describes the linear relationship between mass and acceleration when it comes to force and leads to the formula F = ma or force equals mass multiplied by rate of acceleration.

4 If the green box weighs 25 lbs. and is 5 ft. from the fulcrum, how much weight would need to be placed at the blue arrow to balance the lever if the arrow's distance from the fulcrum is 6 ft.?
63% Answer Correctly
0 lbs.
10.42 lbs.
20.83 lbs.
83.33 lbs.
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 Rb, our missing value, and plugging in our variables yields:

Rb = \( \frac{R_ad_a}{d_b} \) = \( \frac{25 lbs. \times 5 ft.}{6 ft.} \) = \( \frac{125 ft⋅lb}{6 ft.} \) = 20.83 lbs.

5

When all forces acting on a system cancel each other out, this is called:

80% Answer Correctly

potential energy

equilibrium

rest

stasis
Solution

When a system is stable or balanced (equilibrium) all forces acting on the system cancel each other out. In the case of torque, equilibrium means that the sum of the anticlockwise moments about a center of rotation equal the sum of the clockwise moments.