ASVAB Mechanical Comprehension Practice Test 922289 Results

Your Results Global Average
Questions 5 5
Correct 0 2.94
Score 0% 59%

Review

1

Which of the following is not a type of simple machine?

58% Answer Correctly

screw

lever

gear

pulley
Solution

The six types of simple machines are the lever, wheel and axle, pulley, inclined plane, wedge, and screw.

2

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

59% Answer Correctly

the portions of the system at an altitude below the input

all of these are correct

everywhere in the system

the portions of the system at an altitude above 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 If 55 lbs. of force is applied 6 ft. from the fulcrum at the blue arrow and the green box is 5 ft. from the fulcrum, how much would the green box have to weigh to balance the lever?
62% Answer Correctly
264 lbs.
132 lbs.
0 lbs.
66 lbs.
Solution

To balance this lever the torques at the green box and the blue arrow must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:

Rada = Rbdb

where a represents the green box and b the blue arrow, R is resistance (weight/force) and d is the distance from the fulcrum.

Solving for Ra, our missing value, and plugging in our variables yields:

Ra = \( \frac{R_bd_b}{d_a} \) = \( \frac{55 lbs. \times 6 ft.}{5 ft.} \) = \( \frac{330 ft⋅lb}{5 ft.} \) = 66 lbs.

4 20 lbs. of effort is used by a machine to lift a 160 lbs. box. What is the mechanical advantage of the machine?
84% Answer Correctly
17
8
2
8.8
Solution

Mechanical advantage is resistance force divided by effort force:

MA = \( \frac{F_r}{F_e} \) = \( \frac{160 lbs.}{20 lbs.} \) = 8

5

What's the last gear in a gear train called?

38% Answer Correctly

idler gear

output gear

driver gear

driven gear
Solution

A gear train is two or more gears linked together. Gear trains are designed to increase or reduce the speed or torque outpout of a rotating system or change the direction of its output. The first gear in the chain is called the driver and the last gear in the chain the driven gear with the gears between them called idler gears.