ASVAB Mechanical Comprehension Practice Test 51272 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.85
Score	0%	57%

Review

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

45% Answer Correctly

	force or speed
	speed or power
	power or distance
	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.

Which class of lever offers no mechanical advantage?

45% Answer Correctly

	third
	first
	none of these, all levers offer mechanical advantage
	second

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.

3 If the handles of a wheelbarrow are 1.0 ft. from the wheel axle, how many pounds of force must you exert to lift the handles if it's carrying a 160 lbs. load concentrated at a point 1.5 ft. from the axle?

52% Answer Correctly

	-54
	47.5
	476.4
	240

Solution

This problem describes a second-class lever and, for a second class lever, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance: F_ed_e = F_rd_r. In this problem we're looking for effort force:
\( F_e = \frac{F_r d_r}{d_e} \)
\( F_e = \frac{160 \times 1.5}{1.0} \)
\( F_e = \frac{240.0}{1.0} \)
\( F_e = 240 \)

The work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. This defines which of the following?

60% Answer Correctly

	Pascal's law
	mechanical advantage
	conservation of mechanical energy
	work-energy theorem

Solution

The work-energy theorem states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. Simply put, work imparts kinetic energy to the matter upon which the work is being done.

Drag is a type of:

81% Answer Correctly

	friction
	work
	kinetic energy
	potential energy

Solution

Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area.