ASVAB Mechanical Comprehension Practice Test 931077 Results

Your Results Global Average
Questions 5 5
Correct 0 2.97
Score 0% 59%

Review

1

What's the first gear in a gear train called?

57% Answer Correctly

driver gear

idler gear

input gear

driven gear


Solution

A gear train is two or more gears linked together. Gear trains are designed to increase or reduce the speed or torque outpout of a rotating system or change the direction of its output. The first gear in the chain is called the driver and the last gear in the chain the driven gear with the gears between them called idler gears.


2 A 410 lb. barrel is rolled up a 11 ft. ramp to a platform that's 5 ft. tall. What effort is required to move the barrel?
53% Answer Correctly
186.4 lbs.
559.1 lbs.
62.1 lbs.
185.4 lbs.

Solution

This problem describes an inclined plane and, for an inclined plane, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance:

Fede = Frdr

Plugging in the variables from this problem yields:

Fe x 11 ft. = 410 lbs. x 5 ft.
Fe = \( \frac{2050 ft⋅lb}{11 ft.} \) = 186.4 lbs.


3

Potential energy is energy that has the potential to be converted into what?

81% Answer Correctly

work

power

 kinetic energy

heat


Solution

Potential energy is the energy of an object by virtue of its position relative to other objects. It is energy that has the potential to be converted into kinetic energy.


4

The mechanical advantage of a third class lever is always:

37% Answer Correctly

greater than one

equal to one

less than one

not equal to 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.


5

A a seesaw / teeter-totter is an example of which of the following?

69% Answer Correctly

inclined plane

third-class lever

first-class lever

second-class lever


Solution

A first-class lever is used to increase force or distance while changing the direction of the force. The lever pivots on a fulcrum and, when a force is applied to the lever at one side of the fulcrum, the other end moves in the opposite direction. The position of the fulcrum also defines the mechanical advantage of the lever. If the fulcrum is closer to the force being applied, the load can be moved a greater distance at the expense of requiring a greater input force. If the fulcrum is closer to the load, less force is required but the force must be applied over a longer distance. An example of a first-class lever is a seesaw / teeter-totter.