ASVAB Mechanical Comprehension Practice Test 225667 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.96
Score	0%	59%

Review

Which of the following is not a type of simple machine?

58% Answer Correctly

	screw
	pulley
	lever
	gear

Solution

The six types of simple machines are the lever, wheel and axle, pulley, inclined plane, wedge, and screw.

Assuming force applied remains constant, which of the following will result in more work being done?

53% Answer Correctly

	moving the object with more speed
	increasing the coefficient of friction
	moving the object farther
	moving the object with more acceleration

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.

3 If the radius of the axle is 3 and the radius of the wheel is 8, what is the mechanical advantage of this wheel and axle configuration?

36% Answer Correctly

	3
	2
	8
	1

Solution

The mechanical advantage of a wheel and axle lies in the difference in radius between the inner (axle) wheel and the outer wheel. But, this mechanical advantage is only realized when the input effort and load are applied to different wheels. Applying both input effort and load to the same wheel results in a mechanical advantage of 1.

4 80 lbs. of effort is used by a machine to lift a 480 lbs. box. What is the mechanical advantage of the machine?

84% Answer Correctly

	6
	7.5
	-3
	6.6

Solution

Mechanical advantage is resistance force divided by effort force:

MA = \( \frac{F_r}{F_e} \) = \( \frac{480 lbs.}{80 lbs.} \) = 6

What defines the mechanical advantage of a first class lever?

65% Answer Correctly

	position of the fulcrum
	input force
	output distance
	output force

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.