ASVAB Mechanical Comprehension Practice Test 420082 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.16
Score	0%	63%

Review

Which of the following is not true of a first-class lever?

51% Answer Correctly

	increases distance
	changes the direction of force
	increases force
	decreases distance

Solution

A first-class lever is used to increase force or distance while changing the direction of the force. The lever pivots on a fulcrum and, when a force is applied to the lever at one side of the fulcrum, the other end moves in the opposite direction. The position of the fulcrum also defines the mechanical advantage of the lever. If the fulcrum is closer to the force being applied, the load can be moved a greater distance at the expense of requiring a greater input force. If the fulcrum is closer to the load, less force is required but the force must be applied over a longer distance. An example of a first-class lever is a seesaw / teeter-totter.

A wedge is most similar to what other type of simple machine?

70% Answer Correctly

	first-class lever
	second-class lever
	inclined plane
	third-class lever

Solution

The wedge is a moving inclined plane that is used to lift, hold, or break apart an object. A wedge converts force applied to its blunt end into force perpendicular to its inclined surface. In contrast to a stationary plane where force is applied to the object being moved, with a wedge the object is stationary and the force is being applied to the plane. Examples of a wedge include knives and chisels.

A wedge converts force applied to its blunt end into force __________ its inclined surface.

57% Answer Correctly

	opposite to
	perpendicular to
	parallel to
	along

Solution

4 If input effort is 700 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 8?

79% Answer Correctly

	11200ft⋅lb
	0ft⋅lb
	5600 ft⋅lb
	1400ft⋅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 8 will multiply an input effort of 700 ft⋅lb by 8 to produce an output effort of 5600 ft⋅lb.

What is the first step to solving a problem where multiple forces are acting on an object?

61% Answer Correctly

	calculate the net force
	calculate the total force
	calculate potential energy
	calculate kinetic energy

Solution

In mechanics, multiple forces are often acting on a particular object and, taken together, produce the net force acting on that object. Like force, net force is a vector quantity in that it has magnitude and direction.