ASVAB Mechanical Comprehension Practice Test 57223 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.82
Score	0%	56%

Review

1 A mass of air has a pressure of 6.0 psi and a volume of 30 ft.³. If the air is compressed to a new volume of 15 ft.³, what is the new pressure?

56% Answer Correctly

	12 psi
	15 psi
	24 psi
	36 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 = 15 ft.³, V₁ = 30 ft.³ and P₁ = 6.0 psi. Solving for P₂:

P₂ = \( \frac{P_1}{\frac{V_2}{V_1}} \) = \( \frac{6.0 psi}{\frac{15 ft.^3}{30 ft.^3}} \) = 12 psi

Force of friction due to kinetic friction is __________ the force of friction due to static friction.

40% Answer Correctly

	lower than
	opposite
	higher than
	the same as

Solution

The formula for force of friction (F_f) is the same whether kinetic or static friction applies: F_{f =}μF_N. To distinguish between kinetic and static friction, μ_k and μ_s are often used in place of μ.

The science that deals with motion and the forces that produce motion is called which of the following?

57% Answer Correctly

	physics
	aeronautics
	mechanics
	engineering

Solution

Mechanics deals with motion and the forces that produce motion.

4 If the green arrow in this diagram represents 750 ft⋅lb of work, how far will the box move if it weighs 250 pounds?

73% Answer Correctly

	6 ft.
	83 ft.
	3 ft.
	12 ft.

Solution

The Law of Work states that the work put into a machine is equal to the work received from the machine under ideal conditions. In equation form, that's:

W_in = W_out
F_effort x d_effort = F_resistance x d_resistance

In this problem, the effort work is 750 ft⋅lb and the resistance force is 250 lbs. and we need to calculate the resistance distance:

W_in = F_resistance x d_resistance
750 ft⋅lb = 250 lbs. x d_resistance
d_resistance = \( \frac{750ft⋅lb}{250 lbs.} \) = 3 ft.

A wedge converts force applied to its blunt end into force __________ its inclined surface.

57% Answer Correctly

	along
	perpendicular to
	opposite to
	parallel to

Solution

The wedge is a moving inclined plane that is used to lift, hold, or break apart an object. A wedge converts force applied to its blunt end into force perpendicular to its inclined surface. In contrast to a stationary plane where force is applied to the object being moved, with a wedge the object is stationary and the force is being applied to the plane. Examples of a wedge include knives and chisels.