ASVAB Mechanical Comprehension Practice Test 993778 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.12
Score	0%	62%

Review

The force exerted on an object due to gravity is called:

70% Answer Correctly

	mass
	density
	potential energy
	weight

Solution

Mass is an intrinsic property of matter and does not vary. Weight is the force exerted on the mass of an object due to gravity and a specific case of Newton's Second Law of Motion. Replace force with weight and acceleration with acceleration due to gravity on Earth (g) and the result is the formula for weight: W = mg or, substituting for g, weight equals mass multiplied by 9.8 m/s².

Which of the following is not true of a first-class lever?

51% Answer Correctly

	changes the direction of force
	decreases distance
	increases distance
	increases force

Solution

A first-class lever is used to increase force or distance while changing the direction of the force. The lever pivots on a fulcrum and, when a force is applied to the lever at one side of the fulcrum, the other end moves in the opposite direction. The position of the fulcrum also defines the mechanical advantage of the lever. If the fulcrum is closer to the force being applied, the load can be moved a greater distance at the expense of requiring a greater input force. If the fulcrum is closer to the load, less force is required but the force must be applied over a longer distance. An example of a first-class lever is a seesaw / teeter-totter.

The principle of moments defines equilibrium in terms of:

54% Answer Correctly

	power
	torque
	energy
	speed

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.

The mass of an object correlates to the size of the object but ultimately depends on:

67% Answer Correctly

	the object's density
	gravity
	the object's weight
	the object's potential energy

Solution

Mass is a measure of the amount of matter in an object. In general, larger objects have larger mass than smaller objects but mass ultimately depends on how compact (dense) a substance is.

5 A = 6 ft., the green box weighs 25 lbs., and the blue box weighs 45 lbs. What does distance B need to be for this lever to balance?

65% Answer Correctly

	1.67 ft.
	0 ft.
	7 ft.
	3.33 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:

f_Ad_A = f_Bd_B

For this problem, the equation becomes:

25 lbs. x 6 ft. = 45 lbs. x d_B

d_B = \( \frac{25 \times 6 ft⋅lb}{45 lbs.} \) = \( \frac{150 ft⋅lb}{45 lbs.} \) = 3.33 ft.