ASVAB Mechanical Comprehension Practice Test 59531 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.68
Score	0%	74%

Review

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

57% Answer Correctly

	oil
	water
	carbon
	air

Solution

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

2 If the green box weighs 70 lbs. and 10 lbs. of force is applied 3 ft. from the fulcrum at the blue arrow, how far from the fulcrum would the green box need to be placed to balance the lever?

55% Answer Correctly

	1.71 ft.
	0.43 ft.
	0.21 ft.
	210 ft.

Solution

To balance this lever the torques at the green box and the blue arrow 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 green box and b the blue arrow, R is resistance (weight/force) and d is the distance from the fulcrum.

Solving for d_a, our missing value, and plugging in our variables yields:

d_a = \( \frac{R_bd_b}{R_a} \) = \( \frac{10 lbs. \times 3 ft.}{70 lbs.} \) = \( \frac{30 ft⋅lb}{70 lbs.} \) = 0.43 ft.

The steering wheel of a car is an example of which type of simple machine?

89% Answer Correctly

	first-class lever
	wheel and axle
	block and tackle
	fixed pulley

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 input effort is 500 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 7?

79% Answer Correctly

	3500 ft⋅lb
	71ft⋅lb
	875ft⋅lb
	0ft⋅lb

Solution

Mechanical advantage is the ratio of output force to input force and tells us by how many times a machine multiplies input effort. So, a machine with a mechanical advantage of 7 will multiply an input effort of 500 ft⋅lb by 7 to produce an output effort of 3500 ft⋅lb.

Which of the following surfaces would have the lowest coefficient of friction?

86% Answer Correctly

	concrete
	tile
	leather
	ice

Solution

Coefficient of friction (μ) represents how much two materials resist sliding across each other. Smooth surfaces like ice have low coefficients of friction while rough surfaces like concrete have high μ.