ASVAB Mechanical Comprehension Practice Test 879453 Results

Your Results Global Average
Questions 5 5
Correct 0 3.17
Score 0% 63%

Review

1

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

54% Answer Correctly

its direction

its speed

its mass

its weight


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.


2 What's the mechanical advantage of a wedge that's 5 inches wide and 40 inches long?
83% Answer Correctly
6
8
7.2
2

Solution

The mechanical advantage (MA) of a wedge is its length divided by its thickness:

MA = \( \frac{l}{t} \) = \( \frac{40 in.}{5 in.} \) = 8


3

Which of the following is not a type of simple machine?

58% Answer Correctly

lever

screw

pulley

gear


Solution

The six types of simple machines are the lever, wheel and axle, pulley, inclined plane, wedge, and screw.


4

A fixed pulley is useful for which of the following?

54% Answer Correctly

multiplying the input force

changing the direction of the output force

multiplying the input distance

changing the direction of the input force


Solution

A fixed pulley is used to change the direction of a force and does not multiply the force applied. As such, it has a mechanical advantage of one. The benefit of a fixed pulley is that it can allow the force to be applied at a more convenient angle, for example, pulling downward or horizontally to lift an object instead of upward.


5

A wedge is most similar to what other type of simple machine?

70% Answer Correctly

third-class lever

inclined plane

second-class lever

first-class lever


Solution

The wedge is a moving inclined plane that is used to lift, hold, or break apart an object. A wedge converts force applied to its blunt end into force perpendicular to its inclined surface. In contrast to a stationary plane where force is applied to the object being moved, with a wedge the object is stationary and the force is being applied to the plane. Examples of a wedge include knives and chisels.