ASVAB Mechanical Comprehension Practice Test 150854 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.11
Score	0%	62%

Review

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

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

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.

2 40 lbs. of effort is used by a machine to lift a 240 lbs. box. What is the mechanical advantage of the machine?

84% Answer Correctly

	6.6
	2
	6
	15

Solution

Mechanical advantage is resistance force divided by effort force:

MA = \( \frac{F_r}{F_e} \) = \( \frac{240 lbs.}{40 lbs.} \) = 6

Lisa lifts a 25 pound box from the floor onto a loading dock 4 ft. off the ground. Sam slides the same box along a ramp to move it up another 4 ft. onto a flatbed truck. Who has done more work?

50% Answer Correctly

	They have done an equal amount of work
	Neither have done any work
	Lisa
	Sam

Solution

Work is force multiplied by distance. Because both Connie and Sam moved the same weight the same distance they have done an equal amount of work. Sam employed the mechnacial advantage of an inclined plane so he exerted less effort to do the work but the amount of work done was still the same.

Which of the following is not a type of simple machine?

58% Answer Correctly

	gear
	lever
	pulley
	screw

Solution

The six types of simple machines are the lever, wheel and axle, pulley, inclined plane, wedge, and screw.

5 If the green arrow in this diagram represents 280 ft⋅lb of work, how far will the box move if it weighs 70 pounds?

72% Answer Correctly

	1 ft.
	8 ft.
	4 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 280 ft⋅lb and the resistance force is 70 lbs. and we need to calculate the resistance distance:

W_in = F_resistance x d_resistance
280 ft⋅lb = 70 lbs. x d_resistance
d_resistance = \( \frac{280ft⋅lb}{70 lbs.} \) = 4 ft.