ASVAB Mechanical Comprehension Practice Test 573171 Results

Your Results Global Average
Questions 5 5
Correct 0 3.23
Score 0% 65%

Review

1

For a hydraulic system, pressure applied to the input of the system will increase the pressure in which parts of the system?

58% Answer Correctly

everywhere in the system

all of these are correct

the portions of the system at an altitude below the input

the portions of the system at an altitude above the input


Solution

Pascal's law states that a pressure change occurring anywhere in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere. For a hydraulic system, this means that a pressure applied to the input of the system will increase the pressure everywhere in the system.


2

Which of these is the formula for kinetic energy?

68% Answer Correctly

\(KE = mgh\)

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

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

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


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 If the green arrow in this diagram represents 320 ft⋅lb of work, how far will the box move if it weighs 80 pounds?
72% Answer Correctly
4 ft.
40 ft.
8 ft.
2 ft.

Solution
The Law of Work states that the work put into a machine is equal to the work received from the machine under ideal conditions. In equation form, that's:

Win = Wout
Feffort x deffort = Fresistance x dresistance

In this problem, the effort work is 320 ft⋅lb and the resistance force is 80 lbs. and we need to calculate the resistance distance:

Win = Fresistance x dresistance
320 ft⋅lb = 80 lbs. x dresistance
dresistance = \( \frac{320ft⋅lb}{80 lbs.} \) = 4 ft.


4

The mechanical advantage of a third class lever is always:

37% Answer Correctly

equal to one

greater than one

not equal to one

less than one


Solution

A third class lever is designed to multiply distance and speed at the expense of effort force. Because the effort force is greater than the resistance, the mechanical advantage of a third class lever is always less than one.

An example of a third class lever is a broom. The fulcrum is at your hand on the end of the broom, the effort force is your other hand in the middle, and the resistance is at the bottom bristles. The effort force of your hand in the middle multiplies the distance and speed of the bristles at the bottom but at the expense of producing a brushing force that's less than the force you're applying with your hand.


5

On Earth, acceleration due to gravity (g) is approximately __________. 

81% Answer Correctly

1 m/s

9.8 m/s2

6.67 x 10-11 m/s2

1 m/s2


Solution

Newton's Law of Univeral Gravitation defines the general formula for the attraction of gravity between two objects:  \(\vec{F_{g}} = { Gm_{1}m_{2} \over r^2}\) . In the specific case of an object falling toward Earth, the acceleration due to gravity (g) is approximately 9.8 m/s2