ASVAB Mechanical Comprehension Practice Test 491661 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.86
Score	0%	57%

Review

Which of the following is the formula for hydraulic pressure?

58% Answer Correctly

	P = F/A²
	P = FA²
	P = F/A
	P = FA

Solution

Hydraulics is the transmission of force through the use of liquids. Liquids are especially suited for transferring force in complex machines because they compress very little and can occupy very small spaces. Hydraulic pressure is calculated by dividing force by the area over which it is applied: P = F/A where F is force in pounds, A is area in square inches, and the resulting pressure is in pounds per square inch (psi).

2 If the radius of the axle is 5 and the radius of the wheel is 8, what is the mechanical advantage of this wheel and axle configuration?

41% Answer Correctly

	1.6
	8
	5
	0.63

Solution

The mechanical advantage of a wheel and axle is the input radius divided by the output radius:

MA = \( \frac{r_i}{r_o} \)

In this case, the input radius (where the effort force is being applied) is 5 and the output radius (where the resistance is being applied) is 8 for a mechanical advantage of \( \frac{5}{8} \) = 0.63

3 A = 8 ft., the green box weighs 50 lbs., and the blue box weighs 90 lbs. What does distance B need to be for this lever to balance?

65% Answer Correctly

	1.48 ft.
	0 ft.
	6 ft.
	4.44 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:

50 lbs. x 8 ft. = 90 lbs. x d_B

d_B = \( \frac{50 \times 8 ft⋅lb}{90 lbs.} \) = \( \frac{400 ft⋅lb}{90 lbs.} \) = 4.44 ft.

According to Boyle's law, for a fixed amount of gas kept at a fixed temperature, which of the following are inversely proportional?

64% Answer Correctly

	volume, mass
	pressure, volume
	density, volume
	pressure, density

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".

Torque involves a perpendicular force applied to a lever arm that moves around a center of rotation. Increasing the length of the lever arm will do which of the following?

55% Answer Correctly

	decrease applied force
	decrease torque
	increase torque
	increase applied force

Solution

Torque measures force applied during rotation: τ = rF. Torque (τ, the Greek letter tau) = the radius of the lever arm (r) multiplied by the force (F) applied. Radius is measured from the center of rotation or fulcrum to the point at which the perpendicular force is being applied. The resulting unit for torque is newton-meter (N-m) or foot-pound (ft-lb).