ASVAB Mechanical Comprehension Practice Test 542151 Results

Your Results Global Average
Questions 5 5
Correct 0 3.41
Score 0% 68%

Review

1

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

81% Answer Correctly

power

 kinetic energy

heat

work
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.

2

Two gears are connected and the larger gear drives the smaller gear. The speed of rotation will __________ and the torque will __________.

61% Answer Correctly

decrease, decrease

increase, increase

decrease, increase

increase, decrease
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.

3 If the handles of a wheelbarrow are 0.5 ft. from the wheel axle and the load is concentrated at a point 1.5 ft. from the axle, how many pounds of load will a 240 lbs. force lift?
47% Answer Correctly
120
80
720
146
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:
\( F_r = \frac{F_e d_e}{d_r} \)
\( F_r = \frac{240 \times 0.5}{1.5} \)
\( F_r = \frac{120.0}{1.5} \)
\( F_r = 80 \)
4 A = 5 ft., the green box weighs 10 lbs., and the blue box weighs 20 lbs. What does distance B need to be for this lever to balance?
65% Answer Correctly
0 ft.
2.5 ft.
2 ft.
1.25 ft.
Solution
In order for this lever to balance, the torque acting on side A must equal the torque acting on side B. Torque is weight x distance from the fulcrum which means that the following must be true for the lever to balance:

fAdA = fBdB

For this problem, the equation becomes:

10 lbs. x 5 ft. = 20 lbs. x dB

dB = \( \frac{10 \times 5 ft⋅lb}{20 lbs.} \) = \( \frac{50 ft⋅lb}{20 lbs.} \) = 2.5 ft.

5

An object's resistance to changes in direction is known as:

82% Answer Correctly

inertia

weight

mass

kinetic energy
Solution

The more mass a substance has the more force is required to move it or to change its direction. This resistance to changes in direction is known as inertia.