ASVAB Mechanical Comprehension Practice Test 326665 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.22
Score	0%	64%

Review

1 If A = 7 ft. and the green box weighs 45 lbs. what is the torque acting on the A side of this lever?

74% Answer Correctly

	105 ft⋅lb
	157 ft⋅lb
	315 ft⋅lb
	945 ft⋅lb

Solution

For a lever, torque is weight x distance from the fulcrum which, in this case, is: 45 ft. x 7 lbs. = 315 ft⋅lb

2 If the radius of the axle is 3 and the radius of the wheel is 4, what is the mechanical advantage of this wheel and axle configuration?

41% Answer Correctly

	0.75
	1
	4
	3

Solution

The mechanical advantage of a wheel and axle is the input radius divided by the output radius:

MA = \( \frac{r_i}{r_o} \)

In this case, the input radius (where the effort force is being applied) is 3 and the output radius (where the resistance is being applied) is 4 for a mechanical advantage of \( \frac{3}{4} \) = 0.75

The force amplification achieved by using a tool, mechanical device or machine system is called:

80% Answer Correctly

	efficiency
	power
	work
	mechanical advantage

Solution

Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Such a device utilizes input force and trades off forces against movement to amplify and/or change its direction.

The force exerted on an object due to gravity is called:

70% Answer Correctly

	mass
	weight
	potential energy
	density

Solution

Mass is an intrinsic property of matter and does not vary. Weight is the force exerted on the mass of an object due to gravity and a specific case of Newton's Second Law of Motion. Replace force with weight and acceleration with acceleration due to gravity on Earth (g) and the result is the formula for weight: W = mg or, substituting for g, weight equals mass multiplied by 9.8 m/s².

5 The radius of the axle is 7, the radius of the wheel is 8, and the blue box weighs 55 lbs. What is the effort force necessary to balance the load?

53% Answer Correctly

	15 lbs.
	7.98 lbs.
	9.12 lbs.
	48.25 lbs.

Solution

The mechanical advantage of a wheel and axle is the input radius divided by the output radius:

MA = \( \frac{r_i}{r_o} \)

In this case, the input radius (where the effort force is being applied) is 8 and the output radius (where the resistance is being applied) is 7 for a mechanical advantage of \( \frac{8}{7} \) = 1.14

MA = \( \frac{load}{effort} \) so effort = \( \frac{load}{MA} \) = \( \frac{55 lbs.}{1.14} \) = 48.25 lbs.