ASVAB Mechanical Comprehension Practice Test 144082 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.42
Score	0%	68%

Review

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

80% Answer Correctly

	power
	mechanical advantage
	work
	efficiency

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.

2 If you lift a 44 lbs. rock 3 ft. from the ground, how much work have you done?

71% Answer Correctly

	132 ft⋅lb
	264 ft⋅lb
	14 ft⋅lb
	None of these is correct

Solution

Work is force times distance. In this case, the force is the weight of the rock so:
\( W = F \times d \)
\( W = 44 \times 3 \)
\( W = 132 \)

A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?

50% Answer Correctly

	in the middle
	near the truck
	near the car
	tension is equal in all parts of the rope

Solution

Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress.

Friction resists movement in a direction __________ to the movement.

81% Answer Correctly

	normal
	perpendicular
	opposite
	parallel

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.

What is work?

60% Answer Correctly

	Force per unit distance
	The potential for exertion
	Force per unit time
	The movement of an object by a force

Solution

Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done. By definition, work is the displacement of an object resulting from applied force.