ASVAB Mechanical Comprehension Practice Test 546311 Results

Your Results Global Average
Questions 5 5
Correct 0 3.39
Score 0% 68%

Review

1

Which of the following is not a characteristic of a ceramic?

61% Answer Correctly

low corrosive action

high melting point

low density

chemically stable


Solution

Ceramics are mixtures of metallic and nonmetallic elements that withstand exteme thermal, chemical, and pressure environments. They have a high melting point, low corrosive action, and are chemically stable. Examples include rock, sand, clay, glass, brick, and porcelain.


2

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

80% Answer Correctly

heat

power

 kinetic energy

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.


3 If 65 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
78 lbs.
26 lbs.
0 lbs.
156 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 = \( \frac{R_bd_b}{d_a} \) = \( \frac{65 lbs. \times 6 ft.}{5 ft.} \) = \( \frac{390 ft⋅lb}{5 ft.} \) = 78 lbs.


4 The radius of the axle is 3, the radius of the wheel is 4, and the blue box weighs 40 lbs. What is the effort force necessary to balance the load?
53% Answer Correctly
5.32 lbs.
30.08 lbs.
4.33 lbs.
3 lbs.

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 4 and the output radius (where the resistance is being applied) is 3 for a mechanical advantage of \( \frac{4}{3} \) = 1.33

MA = \( \frac{load}{effort} \) so effort = \( \frac{load}{MA} \) = \( \frac{40 lbs.}{1.33} \) = 30.08 lbs.


5

Drag is a type of:

81% Answer Correctly

kinetic energy

friction

work

potential energy


Solution

Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area.