ASVAB Mechanical Comprehension Practice Test 285021 Results

Your Results Global Average
Questions 5 5
Correct 0 3.28
Score 0% 66%

Review

1 If the green arrow in this diagram represents 600 ft⋅lb of work, how far will the box move if it weighs 150 pounds?
72% Answer Correctly
8 ft.
2 ft.
4 ft.
1 ft.

Solution
The Law of Work states that the work put into a machine is equal to the work received from the machine under ideal conditions. In equation form, that's:

Win = Wout
Feffort x deffort = Fresistance x dresistance

In this problem, the effort work is 600 ft⋅lb and the resistance force is 150 lbs. and we need to calculate the resistance distance:

Win = Fresistance x dresistance
600 ft⋅lb = 150 lbs. x dresistance
dresistance = \( \frac{600ft⋅lb}{150 lbs.} \) = 4 ft.


2

What type of load is sudden and for a relatively short duration?

69% Answer Correctly

non-uniformly distributed load

impact load

concentrated load

dynamic load


Solution

A concentrated load acts on a relatively small area of a structure, a static uniformly distributed load doesn't create specific stress points or vary with time, a dynamic load varies with time or affects a structure that experiences a high degree of movement, an impact load is sudden and for a relatively short duration and a non-uniformly distributed load creates different stresses at different locations on a structure.


3 A mass of air has a pressure of 12.0 psi and a volume of 60 ft.3. If the air is compressed to a new volume of 40 ft.3, what is the new pressure?
56% Answer Correctly
36 psi
18 psi
21 psi
20 psi

Solution

According to Boyle's Law, pressure and volume are inversely proportional:

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

In this problem, V2 = 40 ft.3, V1 = 60 ft.3 and P1 = 12.0 psi. Solving for P2:

P2 = \( \frac{P_1}{\frac{V_2}{V_1}} \) = \( \frac{12.0 psi}{\frac{40 ft.^3}{60 ft.^3}} \) = 18 psi


4

The principle of moments defines equilibrium in terms of:

53% Answer Correctly

power

energy

speed

torque


Solution

According to the principle of moments, you can maintain equilibrium if the moments (forces) tending to clockwise rotation are equal to the moments tending to counterclockwise rotation. Another name for these moments of force is torque.


5

A ramp is an example of which kind of simple machine?

84% Answer Correctly

wedge

none of these

first-class lever

inclined plane


Solution

An inclined plane is a simple machine that reduces the force needed to raise an object to a certain height. Work equals force x distance and, by increasing the distance that the object travels, an inclined plane reduces the force necessary to raise it to a particular height. In this case, the mechanical advantage is to make the task easier. An example of an inclined plane is a ramp.