ASVAB Mechanical Comprehension Practice Test 369976 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.42
Score	0%	68%

Review

The principle of conservation of mechanical energy states that, as long as no other forces are applied, what will remain constant as an object falls?

45% Answer Correctly

	potential energy
	acceleration
	total mechanical energy
	kinetic energy

Solution

As an object falls, its potential energy is converted into kinetic energy. The principle of conservation of mechanical energy states that, as long as no other forces are applied, total mechanical energy (PE + KE) of the object will remain constant at all points in its descent.

Hydraulics is the transmission of force through the use of which of the following?

74% Answer Correctly

	air pressure
	gear systems
	liquids
	torque

Solution

Hydraulics is the transmission of force through the use of liquids. Liquids are especially suited for transferring force in complex machines because they compress very little and can occupy very small spaces. Hydraulic pressure is calculated by dividing force by the area over which it is applied: P = F/A where F is force in pounds, A is area in square inches, and the resulting pressure is in pounds per square inch (psi).

3 A = 4 ft., the green box weighs 10 lbs., and the blue box weighs 45 lbs. What does distance B need to be for this lever to balance?

65% Answer Correctly

	3.56 ft.
	0.22 ft.
	0 ft.
	0.89 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:

10 lbs. x 4 ft. = 45 lbs. x d_B

d_B = \( \frac{10 \times 4 ft⋅lb}{45 lbs.} \) = \( \frac{40 ft⋅lb}{45 lbs.} \) = 0.89 ft.

The force required to initally get an object moving is __________ the force required to keep it moving.

76% Answer Correctly

	opposite
	the same as
	higher than
	lower than

Solution

For any given surface, the coefficient of static friction is higher than the coefficient of kinetic friction. More force is required to initally get an object moving than is required to keep it moving. Additionally, static friction only arises in response to an attempt to move an object (overcome the normal force between it and the surface).

5 50 lbs. of effort is used by a machine to lift a 150 lbs. box. What is the mechanical advantage of the machine?

84% Answer Correctly

	2.7
	3.3
	8
	3

Solution

Mechanical advantage is resistance force divided by effort force:

MA = \( \frac{F_r}{F_e} \) = \( \frac{150 lbs.}{50 lbs.} \) = 3