ASVAB Mechanical Comprehension Practice Test 62667 Results

Your Results Global Average
Questions 5 5
Correct 0 3.22
Score 0% 64%

Review

1 If the green box weighs 40 lbs. and is 5 ft. from the fulcrum, how far from the fulcrum would a 40 lbs. weight need to be placed to balance the lever?
61% Answer Correctly
2.5 ft.
10 ft.
5 ft.
200 ft.
Solution

To balance this lever the torques on each side of the fulcrum must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:

Rada = Rbdb

where a represents the left side of the fulcrum and b the right, R is resistance (weight) and d is the distance from the fulcrum.

Solving for db, our missing value, and plugging in our variables yields:

db = \( \frac{R_ad_a}{R_b} \) = \( \frac{40 lbs. \times 5 ft.}{40 lbs.} \) = \( \frac{200 ft⋅lb}{40 lbs.} \) = 5 ft.

2

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

pressure, volume

volume, mass

density, 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".

3

Normal force is generally equal to the __________ of an object.

61% Answer Correctly

density

weight

mass

coefficient of friction
Solution

Normal force arises on a flat horizontal surface in response to an object's weight pressing it down. Consequently, normal force is generally equal to the object's weight.

4

An inclined plane increases ___________ to reduce ____________.

58% Answer Correctly

distance, force

force, distance

distance, power

force, power
Solution

An inclined plane is a simple machine that reduces the force needed to raise an object to a certain height. Work equals force x distance and, by increasing the distance that the object travels, an inclined plane reduces the force necessary to raise it to a particular height. In this case, the mechanical advantage is to make the task easier. An example of an inclined plane is a ramp.

5 If input effort is 100 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 7?
79% Answer Correctly
14ft⋅lb
175ft⋅lb
350ft⋅lb
700 ft⋅lb
Solution
Mechanical advantage is the ratio of output force to input force and tells us by how many times a machine multiplies input effort. So, a machine with a mechanical advantage of 7 will multiply an input effort of 100 ft⋅lb by 7 to produce an output effort of 700 ft⋅lb.