ASVAB Mechanical Comprehension Practice Test 649343 Results

Your Results Global Average
Questions 5 5
Correct 0 3.14
Score 0% 63%

Review

1 If you lift a 38 lbs. rock 18 ft. from the ground, how much work have you done?
71% Answer Correctly
None of these is correct
56 ft⋅lb
684 ft⋅lb
0 ft⋅lb

Solution
Work is force times distance. In this case, the force is the weight of the rock so:
\( W = F \times d \)
\( W = 38 \times 18 \)
\( W = 684 \)

2

For a hydraulic system, pressure applied to the input of the system will increase the pressure in which parts of the system?

58% Answer Correctly

the portions of the system at an altitude above the input

all of these are correct

everywhere in the system

the portions of the system at an altitude below the input


Solution

Pascal's law states that a pressure change occurring anywhere in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere. For a hydraulic system, this means that a pressure applied to the input of the system will increase the pressure everywhere in the system.


3

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.


4

Which of the following is the formula for torque?

61% Answer Correctly

τ = F/r2

τ = F/r

τ = rF

τ = r/F


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).


5

Boyle's law defines the relationship between pressure and volume as:

57% Answer Correctly

\(\frac{P_1}{P_2} = \frac{V_1}{V_2}\)

\(\frac{P_1}{P_2} = {V_1}{V_2}\)

\({P_1}{P_2} = {V_1}{V_2}\)

\(\frac{P_1}{P_2} = \frac{V_2}{V_1}\)


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". Expressed as a formula, that's \(\frac{P_1}{P_2} = \frac{V_2}{V_1}\)