ASVAB Mechanical Comprehension Practice Test 926221 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.10
Score	0%	62%

Review

1 If input effort is 600 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 9?

79% Answer Correctly

	10800ft⋅lb
	66ft⋅lb
	5400 ft⋅lb
	21600ft⋅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 9 will multiply an input effort of 600 ft⋅lb by 9 to produce an output effort of 5400 ft⋅lb.

2 What's the mechanical advantage of a wedge that's 3 inches wide and 21 inches long?

83% Answer Correctly

	14
	7.7
	6.3
	7

Solution

The mechanical advantage (MA) of a wedge is its length divided by its thickness:

MA = \( \frac{l}{t} \) = \( \frac{21 in.}{3 in.} \) = 7

Which of the following will increase the mechanical advantage of a second-class lever?

55% Answer Correctly

	decrease the length of the lever
	move the object being lifted farther away from the fulcrum
	move the fulcrum between the force and the object being lifted
	move the object being lifted closer to the fulcrum

Solution

A second-class lever is used to increase force on an object in the same direction as the force is applied. This lever requires a smaller force to lift a larger load but the force must be applied over a greater distance. The fulcrum is placed at one end of the lever and mechanical advantage increases as the object being lifted is moved closer to the fulcrum or the length of the lever is increased. An example of a second-class lever is a wheelbarrow.

Which class of lever offers no mechanical advantage?

45% Answer Correctly

	third
	first
	second
	none of these, all levers offer mechanical advantage

Solution

A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers.

Which of the following is not a type of structural load?

49% Answer Correctly

	live load
	dead load
	wind load
	occupancy load

Solution

Dead load is the weight of the building and materials, live load is additional weight due to occupancy or use, snow load is the weight of accumulated snow on a structure and wind load is the force of wind pressures against structure surfaces.