ASVAB Mechanical Comprehension Practice Test 179354 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.31
Score	0%	66%

Review

Potential energy is energy that has the potential to be converted into what?

80% Answer Correctly

	kinetic energy
	heat
	work
	power

Solution

Potential energy is the energy of an object by virtue of its position relative to other objects. It is energy that has the potential to be converted into kinetic energy.

2 If A = 5 ft. and the green box weighs 15 lbs. what is the torque acting on the A side of this lever?

75% Answer Correctly

	18 ft⋅lb
	75 ft⋅lb
	150 ft⋅lb
	300 ft⋅lb

Solution

For a lever, torque is weight x distance from the fulcrum which, in this case, is: 15 ft. x 5 lbs. = 75 ft⋅lb

The mechanical advantage of a wheel and axle is equal to the:

61% Answer Correctly

	ratio of the diameters of the wheels
	difference in the lengths of the axles
	difference in the diameters of the wheels
	length of the axle

Solution

A wheel and axle uses two different diameter wheels mounted to a connecting axle. Force is applied to the larger wheel and large movements of this wheel result in small movements in the smaller wheel. Because a larger movement distance is being translated to a smaller distance, force is increased with a mechanical advantage equal to the ratio of the diameters of the wheels. An example of a wheel and axle is the steering wheel of a car.

4 If a 60 lbs. weight is placed 7 ft. from the fulcrum at the blue arrow and the green box is 2 ft. from the fulcrum, how much would the green box have to weigh to balance the lever?

61% Answer Correctly

	210 lbs.
	0 lbs.
	70 lbs.
	105 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:

R_ad_a = R_bd_b

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 R_a, our missing value, and plugging in our variables yields:

R_a = \( \frac{R_bd_b}{d_a} \) = \( \frac{60 lbs. \times 7 ft.}{2 ft.} \) = \( \frac{420 ft⋅lb}{2 ft.} \) = 210 lbs.

The principle of moments defines equilibrium in terms of:

53% Answer Correctly

	speed
	energy
	power
	torque

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.