ASVAB Mechanical Comprehension Practice Test 332998 Results

Your Results Global Average
Questions 5 5
Correct 0 3.01
Score 0% 60%

Review

1

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

69% Answer Correctly

impact load

dynamic load

concentrated load

non-uniformly distributed 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.


2

Which of these is the formula for kinetic energy?

67% Answer Correctly

\(KE = {1 \over 2}mh^2\)

\(KE = {1 \over 2}mv^2\)

\(KE = {m \over v^2 }\)

\(KE = mgh\)


Solution

Kinetic energy is the energy of movement and is a function of the mass of an object and its speed: \(KE = {1 \over 2}mv^2\) where m is mass in kilograms, v is speed in meters per second, and KE is in joules. The most impactful quantity to kinetic energy is velocity as an increase in mass increases KE linearly while an increase in speed increases KE exponentially.


3 A 230 lb. barrel is rolled up a 16 ft. ramp to a platform that's 3 ft. tall. What effort is required to move the barrel?
53% Answer Correctly
64.7 lbs.
21.6 lbs.
46.1 lbs.
43.1 lbs.

Solution

This problem describes an inclined plane and, for an inclined plane, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance:

Fede = Frdr

Plugging in the variables from this problem yields:

Fe x 16 ft. = 230 lbs. x 3 ft.
Fe = \( \frac{690 ft⋅lb}{16 ft.} \) = 43.1 lbs.


4

Which of the following statements about drag is false?

58% Answer Correctly

slower objects experience more drag than faster objects

drag occurs during movement through a fluid

the amount of drag depends on the speed of an object

the amount of drag depends on the shape of an object


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.


5 A mass of air has a pressure of 9.0 psi and a volume of 45 ft.3. If the air is compressed to a new volume of 35 ft.3, what is the new pressure?
56% Answer Correctly
10.4 psi
34.7 psi
13.6 psi
11.6 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 = 35 ft.3, V1 = 45 ft.3 and P1 = 9.0 psi. Solving for P2:

P2 = \( \frac{P_1}{\frac{V_2}{V_1}} \) = \( \frac{9.0 psi}{\frac{35 ft.^3}{45 ft.^3}} \) = 11.6 psi