ASVAB Mechanical Comprehension Practice Test 48186 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.86
Score	0%	57%

Review

Concurrent forces:

55% Answer Correctly

	act in a common dimension
	pass through a common point
	act in a common plane
	act along the same line of action

Solution

Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.

2 What is the efficiency of a machine has work input of 165 ft⋅lb and work output of 123 ft⋅lb?

67% Answer Correctly

	75%
	150%
	300%
	37%

Solution

Due to friction, a machine will never be able to utilize 100% of its work input. A certain percentage of that input will be lost in overcoming friction within the machine. Effeciency is a measure of how much of a machine's work input can be turned into useful work output and is calculated by dividing work output by work input and multiplying the result by 100:
\( Efficiency = \frac{Work_{out}}{Work_{in}} \times 100 \) \( = \frac{123 ft⋅lb}{165 ft⋅lb} \times 100 \) \( = 75% \) %

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

	all of these are correct
	everywhere in the system
	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.

Which of the following represents the force a surface exerts when an object presses against it?

48% Answer Correctly

	normal force
	counter force
	mass
	friction

Solution

Normal force (F_N) represents the force a surface exerts when an object presses against it.

What is work?

60% Answer Correctly

	Force per unit distance
	The potential for exertion
	The movement of an object by a force
	Force per unit time

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. By definition, work is the displacement of an object resulting from applied force.