ASVAB Mechanical Comprehension Practice Test 202673 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.74
Score	0%	75%

Review

1 If input effort is 400 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 7?

79% Answer Correctly

	11200ft⋅lb
	700ft⋅lb
	0ft⋅lb
	2800 ft⋅lb

Solution

Mechanical advantage is the ratio of output force to input force and tells us by how many times a machine multiplies input effort. So, a machine with a mechanical advantage of 7 will multiply an input effort of 400 ft⋅lb by 7 to produce an output effort of 2800 ft⋅lb.

2 How much resistance could a 205 lb. effort force lift using a block and tackle pulley that has 4 ropes supporting the resistance?

81% Answer Correctly

	902 lbs.
	2460 lbs.
	817 lbs.
	820 lbs.

Solution

The mechanical advantage (MA) of a block and tackle pulley is equal to the number of times the effort force changes direction. An easy way to count how many times the effort force changes direction is to count the number of ropes that support the resistance which, in this problem, is 4. With a MA of 4, a 205 lbs. effort force could lift 205 lbs. x 4 = 820 lbs. resistance.

3 What's the mechanical advantage of a wedge that's 5 inches wide and 45 inches long?

83% Answer Correctly

	9
	11
	10.5
	9.9

Solution

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

MA = \( \frac{l}{t} \) = \( \frac{45 in.}{5 in.} \) = 9

The standard unit of energy is the:

73% Answer Correctly

	Volt
	Joule
	Horsepower
	Watt

Solution

The Joule (J) is the standard unit of energy and has the unit \({kg \times m^2} \over s^2\).

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
	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.