ASVAB Mechanical Comprehension Practice Test 697080 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.63
Score	0%	73%

Review

1 If input effort is 700 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 5?

79% Answer Correctly

	3500 ft⋅lb
	875ft⋅lb
	140ft⋅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 5 will multiply an input effort of 700 ft⋅lb by 5 to produce an output effort of 3500 ft⋅lb.

When all forces acting on a system cancel each other out, this is called:

80% Answer Correctly

	equilibrium
	potential energy
	stasis
	rest

Solution

When a system is stable or balanced (equilibrium) all forces acting on the system cancel each other out. In the case of torque, equilibrium means that the sum of the anticlockwise moments about a center of rotation equal the sum of the clockwise moments.

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

77% Answer Correctly

	concrete
	steel
	marble
	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.

4 A mass of air has a pressure of 15.0 psi and a volume of 75 ft.³. If the air is compressed to a new volume of 50 ft.³, what is the new pressure?

56% Answer Correctly

	31.5 psi
	22.5 psi
	24.5 psi
	11.3 psi

Solution

According to Boyle's Law, pressure and volume are inversely proportional:

\( \frac{P_1}{P_2} \) = \( \frac{V_2}{V_1} \)

In this problem, V₂ = 50 ft.³, V₁ = 75 ft.³ and P₁ = 15.0 psi. Solving for P₂:

P₂ = \( \frac{P_1}{\frac{V_2}{V_1}} \) = \( \frac{15.0 psi}{\frac{50 ft.^3}{75 ft.^3}} \) = 22.5 psi

Friction resists movement in a direction __________ to the movement.

81% Answer Correctly

	parallel
	opposite
	perpendicular
	normal

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.