ASVAB Mechanical Comprehension Practice Test 492546 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.63
Score	0%	53%

Review

A fixed pulley has a mechanical advantage of:

68% Answer Correctly

	0
	-1
	2
	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.

What type of load doesn't create specific stress points or vary with time?

60% Answer Correctly

	concentrated load
	static uniformly distributed load
	impact load
	non-uniformly distributed load

Solution

A concentrated load acts on a relatively small area of a structure, a static uniformly distributed load doesn't create specific stress points or vary with time, a dynamic load varies with time or affects a structure that experiences a high degree of movement, an impact load is sudden and for a relatively short duration and a non-uniformly distributed load creates different stresses at different locations on a structure.

3 What is the power output of a 6 hp engine that's 35% efficient?

40% Answer Correctly

	4620 \( \frac{ft⋅lb}{s} \)
	288.8 \( \frac{ft⋅lb}{s} \)
	3465 \( \frac{ft⋅lb}{s} \)
	1155 \( \frac{ft⋅lb}{s} \)

Solution

\( Efficiency = \frac{Power_{out}}{Power_{in}} \times 100 \)
Solving for power out: \( P_{o} = \frac{E \times P_{i}}{100} \)
Knowing that 1 hp = 550 \( \frac{ft⋅lb}{s} \), P_i becomes 6 hp x 550 \( \frac{ft⋅lb}{s} \) = 3300 \( \frac{ft⋅lb}{s} \)
\( P_{o} = \frac{E \times P_{i}}{100} = \frac{35 \times 3300 \frac{ft⋅lb}{s}}{100} \) \( = \frac{115500 \frac{ft⋅lb}{s}}{100} \) = 1155 \( \frac{ft⋅lb}{s} \)

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

57% Answer Correctly

	opposite to
	parallel to
	along
	perpendicular to

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.

The advantage of using a third-class lever is that it increases:

37% Answer Correctly

	the force applied to the load
	the mechanical advantage of the lever
	the speed of the load
	the distance traveled by the load

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.