ASVAB Mechanical Comprehension Practice Test 669163 Results

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

Review

1

If the handles of a wheelbarrow are 3 ft. from the wheel axle, what force must you exert to lift the handles if it's carrying a 270 lb. load concentrated at a point 0.5 ft. from the axle?

56% Answer Correctly

90 lbs

810 lbs

45 lbs

0.83 lbs


Solution

This problem describes a second-class lever and, for a second class lever, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance: Fede = Frdr. Plugging in the variables from this problem yields:

Fe x 3 ft. = 270 lbs x 0.5 ft
Fe = 135 ft-lb. / 3 ft 
F= 45 lbs


2

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

the portions of the system at an altitude below the input

everywhere in the system

the portions of the system at an altitude above the input

all of these are correct


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.


3

Which of these is the formula for kinetic energy?

68% Answer Correctly

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

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

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

\(KE = mgh\)


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.


4

Hydraulics is the transmission of force through the use of which of the following?

74% Answer Correctly

liquids

torque

air pressure

gear systems


Solution

Hydraulics is the transmission of force through the use of liquids. Liquids are especially suited for transferring force in complex machines because they compress very little and can occupy very small spaces. Hydraulic pressure is calculated by dividing force by the area over which it is applied: P = F/A where F is force in pounds, A is area in square inches, and the resulting pressure is in pounds per square inch (psi).


5

Which of the following is not a characteristic of a ceramic?

61% Answer Correctly

high melting point

chemically stable

low corrosive action

low density


Solution

Ceramics are mixtures of metallic and nonmetallic elements that withstand exteme thermal, chemical, and pressure environments. They have a high melting point, low corrosive action, and are chemically stable. Examples include rock, sand, clay, glass, brick, and porcelain.