ASVAB Mechanical Comprehension Practice Test 119019 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.36
Score	0%	67%

Review

Coplanar forces:

62% Answer Correctly

	act in a common plane
	act along the same line of action
	have opposite dimensions
	pass through a common point

Solution

Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.

A watt is the unit for which of the following?

71% Answer Correctly

	mechanical advantage
	power
	energy
	work

Solution

Power is the rate at which work is done, P = w/t, or work per unit time. The watt (W) is the unit for power and is equal to 1 joule (or newton-meter) per second. Horsepower (hp) is another familiar unit of power used primarily for rating internal combustion engines. 1 hp equals 746 watts.

The measure of how much of the power put into a machine is turned into movement or force is called:

56% Answer Correctly

	force multiplication
	efficiency
	mechanical advantage
	power

Solution

The efficiency of a machine describes how much of the power put into the machine is turned into movement or force. A 100% efficient machine would turn all of the input power into output movement or force. However, no machine is 100% efficient due to friction, heat, wear and other imperfections that consume input power without delivering any output.

A fixed pulley has a mechanical advantage of:

68% Answer Correctly

	0
	2
	-1
	1

Solution

A fixed pulley is used to change the direction of a force and does not multiply the force applied. As such, it has a mechanical advantage of one. The benefit of a fixed pulley is that it can allow the force to be applied at a more convenient angle, for example, pulling downward or horizontally to lift an object instead of upward.

5 If input effort is 400 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 7?

79% Answer Correctly

	5600ft⋅lb
	2800 ft⋅lb
	700ft⋅lb
	57ft⋅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 7 will multiply an input effort of 400 ft⋅lb by 7 to produce an output effort of 2800 ft⋅lb.