ASVAB Mechanical Comprehension Practice Test 232249 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.89
Score	0%	58%

Review

Which of the following statements about drag is false?

58% Answer Correctly

	the amount of drag depends on the speed of an object
	the amount of drag depends on the shape of an object
	slower objects experience more drag than faster objects
	drag occurs during movement through a fluid

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.

When it comes to force, mass and acceleration have what kind of relationship?

66% Answer Correctly

	exponential
	logarithmic
	inverse
	linear

Solution

Newton's Second Law of Motion states that "The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object." This Law describes the linear relationship between mass and acceleration when it comes to force and leads to the formula F = ma or force equals mass multiplied by rate of acceleration.

3 If the handles of a wheelbarrow are 2.5 ft. from the wheel axle, how many pounds of force must you exert to lift the handles if it's carrying a 100 lbs. load concentrated at a point 1.0 ft. from the axle?

52% Answer Correctly

	-9
	40
	0
	-14

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:
\( F_e = \frac{F_r d_r}{d_e} \)
\( F_e = \frac{100 \times 1.0}{2.5} \)
\( F_e = \frac{100.0}{2.5} \)
\( F_e = 40 \)

Collinear forces:

72% Answer Correctly

	are unrelated to each other
	pass through a common point
	act along the same line of action
	act in a common plane

Solution

Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.

The mechanical advantage of a third class lever is always:

37% Answer Correctly

	less than one
	not equal to one
	equal to one
	greater than one

Solution

A third class lever is designed to multiply distance and speed at the expense of effort force. Because the effort force is greater than the resistance, the mechanical advantage of a third class lever is always less than one.

An example of a third class lever is a broom. The fulcrum is at your hand on the end of the broom, the effort force is your other hand in the middle, and the resistance is at the bottom bristles. The effort force of your hand in the middle multiplies the distance and speed of the bristles at the bottom but at the expense of producing a brushing force that's less than the force you're applying with your hand.