ASVAB Mechanical Comprehension Practice Test 998124 Results

Your Results Global Average
Questions 5 5
Correct 0 3.31
Score 0% 66%

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, volume

density, volume

pressure, density

volume, mass


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

69% Answer Correctly

first-class lever

second-class lever

inclined plane

third-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.


3 If the radius of the axle is 3 and the radius of the wheel is 6, what is the mechanical advantage of this wheel and axle configuration?
36% Answer Correctly
1
0
3
2

Solution

The mechanical advantage of a wheel and axle lies in the difference in radius between the inner (axle) wheel and the outer wheel. But, this mechanical advantage is only realized when the input effort and load are applied to different wheels. Applying both input effort and load to the same wheel results in a mechanical advantage of 1.


4 How much resistance could a 180 lb. effort force lift using a block and tackle pulley that has 10 ropes supporting the resistance?
81% Answer Correctly
1804 lbs.
1800 lbs.
900 lbs.
3600 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 10. With a MA of 10, a 180 lbs. effort force could lift 180 lbs. x 10 = 1800 lbs. resistance.


5 What's the mechanical advantage of a wedge that's 2 inches wide and 14 inches long?
83% Answer Correctly
8.5
9
7
14

Solution

The mechanical advantage (MA) of a wedge is its length divided by its thickness:

MA = \( \frac{l}{t} \) = \( \frac{14 in.}{2 in.} \) = 7