ASVAB Mechanical Comprehension Practice Test 463933 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.98
Score	0%	60%

Review

1 If input effort is 200 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 5?

79% Answer Correctly

	0ft⋅lb
	1000 ft⋅lb
	40ft⋅lb
	4000ft⋅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 5 will multiply an input effort of 200 ft⋅lb by 5 to produce an output effort of 1000 ft⋅lb.

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

53% Answer Correctly

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

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.

A shovel is an example of which class of lever?

56% Answer Correctly

	third
	first
	second
	a shovel is not a lever

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.

A fixed pulley is useful for which of the following?

53% Answer Correctly

	changing the direction of the input force
	multiplying the input force
	changing the direction of the output force
	multiplying the input distance

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.

Boyle's law defines the relationship between pressure and volume as:

58% Answer Correctly

	\({P_1}{P_2} = {V_1}{V_2}\)
	\(\frac{P_1}{P_2} = \frac{V_2}{V_1}\)
	\(\frac{P_1}{P_2} = \frac{V_1}{V_2}\)
	\(\frac{P_1}{P_2} = {V_1}{V_2}\)

Solution

Boyle's law states that "for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional". Expressed as a formula, that's \(\frac{P_1}{P_2} = \frac{V_2}{V_1}\)