ASVAB Mechanical Comprehension Practice Test 200423 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.15
Score	0%	63%

Review

Which of the following represents the force a surface exerts when an object presses against it?

49% Answer Correctly

	normal force
	friction
	mass
	counter force

Solution

Normal force (F_N) represents the force a surface exerts when an object presses against it.

Specific gravity is a comparison of the density of an object with the density of:

57% Answer Correctly

	carbon
	oil
	water
	air

Solution

Specific gravity is the ratio of the density of equal volumes of a substance and water and is measured by a hyrdometer.

Friction resists movement in a direction __________ to the movement.

82% Answer Correctly

	opposite
	parallel
	normal
	perpendicular

Solution

Friction resists movement. Kinetic (also called sliding or dynamic) friction resists movement in a direction opposite to the movement. Because it opposes movement, kinetic friction will eventually bring an object to a stop. An example is a rock that's sliding across ice.

4 A = 6 ft., the green box weighs 25 lbs., and the blue box weighs 65 lbs. What does distance B need to be for this lever to balance?

65% Answer Correctly

	6.92 ft.
	10 ft.
	2.31 ft.
	150 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. = 65 lbs. x d_B

d_B = \( \frac{25 \times 6 ft⋅lb}{65 lbs.} \) = \( \frac{150 ft⋅lb}{65 lbs.} \) = 2.31 ft.

What is work?

61% Answer Correctly

	Force per unit time
	Force per unit distance
	The potential for exertion
	The movement of an object by a force

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.