ASVAB Mechanical Comprehension Practice Test 729739 Results

Your Results Global Average
Questions 5 5
Correct 0 3.46
Score 0% 69%

Review

1 If you have a gear train with two gears, the first with 36 teeth and the second with 4 teeth, how many revolutions does the second gear make for each revolution of the first gear?
78% Answer Correctly
3
12
9
10.5

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 = \( \frac{N_1}{N_2} \) = \( \frac{36}{4} \) = 9


2 If you have a gear train with three gears, the first with 24 teeth, the second with 18 teeth, and the third with 2 teeth, what is its mechanical advantage?
52% Answer Correctly
19
12
13.5
18

Solution

The mechanical advantage of a gear train is its gear ratio. The gear ratio (Vr) 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 three gears so the equation becomes:

Vr = \( \frac{N_1}{N_2} \) \( \frac{N_2}{N_3} \) = \( \frac{24}{18} \) \( \frac{18}{2} \) = \( \frac{24}{2} \) = 12


3

What type of load varies with time or affects a structure that experiences a high degree of movement?

66% Answer Correctly

impact load

concentrated load

static 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.


4

What type of load acts on a relatively small area of a structure?

74% Answer Correctly

concentrated load

non-uniformly distributed load

dynamic load

impact 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

Tension is a force that does which of the following?

76% Answer Correctly

compacts an object

heats up an object

slows an object

stretches an object


Solution

Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress.