ASVAB Mechanical Comprehension Practice Test 699849 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.80
Score	0%	56%

Review

A shovel is an example of which class of lever?

56% Answer Correctly

	a shovel is not a lever
	third
	first
	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.

A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?

50% Answer Correctly

	in the middle
	near the car
	tension is equal in all parts of the rope
	near the truck

Solution

Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress.

3 If the handles of a wheelbarrow are 1.5 ft. from the wheel axle and the load is concentrated at a point 1.0 ft. from the axle, how many pounds of load will a 220 lbs. force lift?

47% Answer Correctly

	146.7
	-50.4
	330
	185.7

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 resistance force:
\( F_r = \frac{F_e d_e}{d_r} \)
\( F_r = \frac{220 \times 1.5}{1.0} \)
\( F_r = \frac{330.0}{1.0} \)
\( F_r = 330 \)

If the handles of a wheelbarrow are 3 ft. from the wheel axle, what force must you exert to lift the handles if it's carrying a 270 lb. load concentrated at a point 0.5 ft. from the axle?

56% Answer Correctly

	0.83 lbs
	90 lbs
	45 lbs
	810 lbs

Solution

F_e x 3 ft. = 270 lbs x 0.5 ft
F_e = 135 ft-lb. / 3 ft
F_e= 45 lbs

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

66% Answer Correctly

	exponential
	linear
	inverse
	logarithmic

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.