ASVAB Mechanical Comprehension Practice Test 66908 Results

Your Results Global Average
Questions 5 5
Correct 0 2.83
Score 0% 57%

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

the portions of the system at an altitude below the input

the portions of the system at an altitude above the input

everywhere in the system

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.


2

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

54% Answer Correctly

its mass

its weight

its direction

its speed


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

Assuming force applied remains constant, which of the following will result in more work being done?

53% Answer Correctly

increasing the coefficient of friction

moving the object with more speed

moving the object farther

moving the object with more acceleration


Solution

Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done.


4

Power is the rate at which:

62% Answer Correctly

work is done

friction is overcome

potential energy is converted into kinetic energy

input force is transferred to output force


Solution

Power is the rate at which work is done, P = w/t, or work per unit time. The watt (W) is the unit for power and is equal to 1 joule (or newton-meter) per second. Horsepower (hp) is another familiar unit of power used primarily for rating internal combustion engines. 1 hp equals 746 watts.


5

A shovel is an example of which class of lever?

56% Answer Correctly

a shovel is not a lever

third

first

second


Solution

A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers.