ASVAB Mechanical Comprehension Practice Test 825684 Results

Your Results Global Average
Questions 5 5
Correct 0 2.84
Score 0% 57%

Review

1

Lisa lifts a 25 pound box from the floor onto a loading dock 4 ft. off the ground. Sam slides the same box along a ramp to move it up another 4 ft. onto a flatbed truck. Who has done more work?

50% Answer Correctly

They have done an equal amount of work

Lisa

Neither have done any work

Sam


Solution

Work is force multiplied by distance. Because both Connie and Sam moved the same weight the same distance they have done an equal amount of work. Sam employed the mechnacial advantage of an inclined plane so he exerted less effort to do the work but the amount of work done was still the same.


2

Depending on where you apply effort and resistance, the wheel and axle can multiply:

45% Answer Correctly

force or distance

force or speed

speed or power

power or distance


Solution

If you apply the resistance to the axle and the effort to the wheel, the wheel and axle will multiply force and if you apply the resistance to the wheel and the effort to the axle, it will multiply speed.


3 If you have a gear train with two gears, the first with 20 teeth and the second with 16 teeth, how many revolutions does the second gear make for each revolution of the first gear?
77% Answer Correctly
2.3
1.3
0.6
-5.8

Solution

The gear ratio (Vr) of a gear train is the product of the gear ratios between the pairs of meshed gears. Let N represent the number of teeth for each gear:

Vr = \( \frac{N_1}{N_2} \) \( \frac{N_2}{N_3} \) \( \frac{N_3}{N_4} \) ... \( \frac{N_n}{N_{n+1}} \)

In this problem, we have only two gears so the equation becomes:

Vr = \( \frac{N_1}{N_2} \) = \( \frac{20}{16} \) = 1.3


4

What type of load doesn't create specific stress points or vary with time?

60% Answer Correctly

non-uniformly distributed load

impact load

static uniformly distributed load

concentrated 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.


5

Which of the following represents how much two materials resist sliding across each other?

53% Answer Correctly

coefficient of friction

normal friction

kinetic friction

static friction


Solution

Coefficient of friction (μ) represents how much two materials resist sliding across each other.  Smooth surfaces like ice have low coefficients of friction while rough surfaces like concrete have high μ.