ASVAB Mechanical Comprehension Practice Test 842663 Results

Your Results Global Average
Questions 5 5
Correct 0 3.43
Score 0% 69%

Review

1

According to Boyle's law, for a fixed amount of gas kept at a fixed temperature, which of the following are inversely proportional?

63% Answer Correctly

pressure, density

volume, mass

density, volume

pressure, volume
Solution

Boyle's law states that "for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional".

2

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.

3 60 lbs. of effort is used by a machine to lift a 120 lbs. box. What is the mechanical advantage of the machine?
84% Answer Correctly
0
1
1.8
2
Solution

Mechanical advantage is resistance force divided by effort force:

MA = \( \frac{F_r}{F_e} \) = \( \frac{120 lbs.}{60 lbs.} \) = 2

4

A wedge is most similar to what other type of simple machine?

70% Answer Correctly

third-class lever

first-class lever

second-class lever

inclined plane
Solution

The wedge is a moving inclined plane that is used to lift, hold, or break apart an object. A wedge converts force applied to its blunt end into force perpendicular to its inclined surface. In contrast to a stationary plane where force is applied to the object being moved, with a wedge the object is stationary and the force is being applied to the plane. Examples of a wedge include knives and chisels.

5 How much resistance could a 85 lb. effort force lift using a block and tackle pulley that has 6 ropes supporting the resistance?
81% Answer Correctly
510 lbs.
513 lbs.
518 lbs.
765 lbs.
Solution

The mechanical advantage (MA) of a block and tackle pulley is equal to the number of times the effort force changes direction. An easy way to count how many times the effort force changes direction is to count the number of ropes that support the resistance which, in this problem, is 6. With a MA of 6, a 85 lbs. effort force could lift 85 lbs. x 6 = 510 lbs. resistance.