ASVAB Mechanical Comprehension Practice Test 964217 Results

Your Results Global Average
Questions 5 5
Correct 0 3.03
Score 0% 61%

Review

1

Which of the following surfaces would have the highest coefficient of friction?

77% Answer Correctly

marble

ice

steel

concrete
Solution

Coefficient of friction (μ) represents how much two materials resist sliding across each other.  Smooth surfaces like ice have low coefficients of friction while rough surfaces like concrete have high μ.

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

volume, mass

pressure, density

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".

3

Which class of lever offers no mechanical advantage?

45% Answer Correctly

none of these, all levers offer mechanical advantage

third

first

second
Solution

A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers.

4 If the handles of a wheelbarrow are 1.0 ft. from the wheel axle and the load is concentrated at a point 0.5 ft. from the axle, how many pounds of load will a 100 lbs. force lift?
47% Answer Correctly
100
147.4
200
50
Solution
This problem describes a second-class lever and, for a second class lever, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance: Fede = Frdr. In this problem we're looking for resistance force:
\( F_r = \frac{F_e d_e}{d_r} \)
\( F_r = \frac{100 \times 1.0}{0.5} \)
\( F_r = \frac{100.0}{0.5} \)
\( F_r = 200 \)
5

Connected gears of different numbers of teeth are used together to change which of the following charasteristics of the input force?

65% Answer Correctly

force

torque

energy

rotational direction
Solution

Connected gears of different numbers of teeth are used together to change the rotational speed and torque of the input force. If the smaller gear drives the larger gear, the speed of rotation will be reduced and the torque will increase. If the larger gear drives the smaller gear, the speed of rotation will increase and the torque will be reduced.