ASVAB Mechanical Comprehension Practice Test 142877 Results

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

Review

What type of load creates different stresses at different locations on a structure?

60% Answer Correctly

	non-uniformly distributed load
	static uniformly distributed load
	impact load
	dynamic 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.

2 If the green arrow in this diagram represents 350 ft⋅lb of work, how far will the box move if it weighs 70 pounds?

72% Answer Correctly

	0 ft.
	5 ft.
	17 ft.
	140 ft.

Solution

The Law of Work states that the work put into a machine is equal to the work received from the machine under ideal conditions. In equation form, that's:

W_in = W_out
F_effort x d_effort = F_resistance x d_resistance

In this problem, the effort work is 350 ft⋅lb and the resistance force is 70 lbs. and we need to calculate the resistance distance:

W_in = F_resistance x d_resistance
350 ft⋅lb = 70 lbs. x d_resistance
d_resistance = \( \frac{350ft⋅lb}{70 lbs.} \) = 5 ft.

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.

4 If A = 4 ft. and the green box weighs 30 lbs. what is the torque acting on the A side of this lever?

74% Answer Correctly

	120 ft⋅lb
	7 ft⋅lb
	240 ft⋅lb
	360 ft⋅lb

Solution

For a lever, torque is weight x distance from the fulcrum which, in this case, is: 30 ft. x 4 lbs. = 120 ft⋅lb

Depending on where you apply effort and resistance, the wheel and axle can multiply:

45% Answer Correctly

	power or distance
	speed or power
	force or speed
	force or distance

Solution

If you apply the resistance to the axle and the effort to the wheel, the wheel and axle will multiply force and if you apply the resistance to the wheel and the effort to the axle, it will multiply speed.