ASVAB Mechanical Comprehension Practice Test 215730 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.98
Score	0%	60%

Review

1 If input effort is 900 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 4?

79% Answer Correctly

	14400ft⋅lb
	1800ft⋅lb
	3600 ft⋅lb
	900ft⋅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 4 will multiply an input effort of 900 ft⋅lb by 4 to produce an output effort of 3600 ft⋅lb.

2 If the radius of the axle is 7 and the radius of the wheel is 8, what is the mechanical advantage of this wheel and axle configuration?

36% Answer Correctly

	1
	8
	0
	7

Solution

The mechanical advantage of a wheel and axle lies in the difference in radius between the inner (axle) wheel and the outer wheel. But, this mechanical advantage is only realized when the input effort and load are applied to different wheels. Applying both input effort and load to the same wheel results in a mechanical advantage of 1.

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

49% Answer Correctly

	normal force
	friction
	counter force
	mass

Solution

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

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

86% Answer Correctly

	tile
	leather
	concrete
	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.

Which of the following is not a modulus of elasticity?

47% Answer Correctly

	shear modulus
	stretch modulus
	stress modulus
	bulk modulus

Solution

The modulus of elasticity measures how much a material or structure will deflect under stress. Stretch modulus is longitudinal stretch (like stretching raw bread dough), shear modulus is longitudinal deflection (like the horizontal displacement of a stack of magzines when a heavy object is placed upon them), and bulk modulus is compression of volume (like the compression of a loaf of bread under a heavy can at the bottom of a grocery bag).