ASVAB Mechanical Comprehension Practice Test 527316 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.09
Score	0%	62%

Review

1 If the green arrow in this diagram represents 800 ft⋅lb of work, how far will the box move if it weighs 160 pounds?

72% Answer Correctly

	10 ft.
	5 ft.
	80 ft.
	1 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 800 ft⋅lb and the resistance force is 160 lbs. and we need to calculate the resistance distance:

W_in = F_resistance x d_resistance
800 ft⋅lb = 160 lbs. x d_resistance
d_resistance = \( \frac{800ft⋅lb}{160 lbs.} \) = 5 ft.

Which of the following is the formula for torque?

61% Answer Correctly

	τ = r/F
	τ = F/r²
	τ = F/r
	τ = rF

Solution

Torque measures force applied during rotation: τ = rF. Torque (τ, the Greek letter tau) = the radius of the lever arm (r) multiplied by the force (F) applied. Radius is measured from the center of rotation or fulcrum to the point at which the perpendicular force is being applied. The resulting unit for torque is newton-meter (N-m) or foot-pound (ft-lb).

3 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

	8
	0
	-1
	1

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.

The standard unit of energy is the:

73% Answer Correctly

	Watt
	Volt
	Horsepower
	Joule

Solution

The Joule (J) is the standard unit of energy and has the unit \({kg \times m^2} \over s^2\).

Which of these is the formula for kinetic energy?

67% Answer Correctly

	\(KE = {1 \over 2}mh^2\)
	\(KE = {m \over v^2 }\)
	\(KE = {1 \over 2}mv^2\)
	\(KE = mgh\)

Solution

Kinetic energy is the energy of movement and is a function of the mass of an object and its speed: \(KE = {1 \over 2}mv^2\) where m is mass in kilograms, v is speed in meters per second, and KE is in joules. The most impactful quantity to kinetic energy is velocity as an increase in mass increases KE linearly while an increase in speed increases KE exponentially.