ASVAB Mechanical Comprehension Practice Test 405418 Results

Your Results Global Average
Questions 5 5
Correct 0 3.53
Score 0% 71%

Review

1

An inclined plane increases ___________ to reduce ____________.

58% Answer Correctly

distance, force

distance, power

force, power

force, distance


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.


2

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

84% Answer Correctly

wedge

inclined plane

first-class lever

none of these


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.


3

The force amplification achieved by using a tool, mechanical device or machine system is called:

80% Answer Correctly

power

mechanical advantage

work

efficiency


Solution

Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Such a device utilizes input force and trades off forces against movement to amplify and/or change its direction.


4

Which of these will have the most impact on the kinetic energy of an object?

54% Answer Correctly

its direction

its weight

its speed

its mass


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.


5 If you have a gear train with two gears, the first with 32 teeth and the second with 4 teeth, how many revolutions does the second gear make for each revolution of the first gear?
77% Answer Correctly
7.2
14
8.8
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 = \( \frac{N_1}{N_2} \) = \( \frac{32}{4} \) = 8