ASVAB Mechanical Comprehension Practice Test 274271 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.93
Score	0%	59%

Review

The principle of conservation of mechanical energy states that, as long as no other forces are applied, what will remain constant as an object falls?

45% Answer Correctly

	potential energy
	total mechanical energy
	kinetic energy
	acceleration

Solution

As an object falls, its potential energy is converted into kinetic energy. The principle of conservation of mechanical energy states that, as long as no other forces are applied, total mechanical energy (PE + KE) of the object will remain constant at all points in its descent.

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

61% Answer Correctly

	mass
	weight
	coefficient of friction
	density

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.

3 A = 6 ft., the green box weighs 40 lbs., and the blue box weighs 80 lbs. What does distance B need to be for this lever to balance?

65% Answer Correctly

	3 ft.
	480 ft.
	13 ft.
	1 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:

f_Ad_A = f_Bd_B

For this problem, the equation becomes:

40 lbs. x 6 ft. = 80 lbs. x d_B

d_B = \( \frac{40 \times 6 ft⋅lb}{80 lbs.} \) = \( \frac{240 ft⋅lb}{80 lbs.} \) = 3 ft.

Sam can do 50 ft. lb. of work in 2 minutes and 5 seconds. What would Sam have to do to increase his power output?

64% Answer Correctly

	do 100 ft. lb. of work in 4 minutes 12 seconds
	do the work in 3 minutes
	do the work in 2 minutes
	do 25 ft. lb. of work in 2 minutes 5 seconds

Solution

Power is the rate of doing work or \(\frac{W}{t}\). To increase power, increase the work being done in the same amount of time or do the same amount of work in less time.

Gear ratio indicates which of the following about two connected gears?

59% Answer Correctly

	mechanical advantage
	work done
	efficiency
	power conversion

Solution

The mechanical advantage (amount of change in speed or torque) of connected gears is proportional to the number of teeth each gear has. Called gear ratio, it's the ratio of the number of teeth on the larger gear to the number of teeth on the smaller gear. For example, a gear with 12 teeth connected to a gear with 9 teeth would have a gear ratio of 4:3.