ASVAB Mechanical Comprehension Practice Test 564194 Results

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

Review

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

73% Answer Correctly

	liquids
	torque
	gear systems
	air pressure

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).

2 How much work can a 9 hp engine do in 2 seconds?

52% Answer Correctly

	9900 ft⋅lb
	18 ft⋅lb
	2 ft⋅lb
	4 ft⋅lb

Solution

Horsepower (hp) is a common measure of power output for complex machines. By definition, a 1 hp machine does 550 ft⋅lb of work in 1 second: 1 hp = 550 ft⋅lb/s. Substituting the variables for this problem gives us:
\( W = 9 hp \times 550 \frac{ft⋅lb}{s} \times 2s = 9900 ft⋅lb \)

A block and tackle with four pulleys would have a mechanical advantage of:

79% Answer Correctly

	4
	2
	0
	1

Solution

Two or more pulleys used together constitute a block and tackle which, unlike a fixed pulley, does impart mechanical advantage as a function of the number of pulleys that make up the arrangement. So, for example, a block and tackle with three pulleys would have a mechanical advantage of three.

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

54% Answer Correctly

	its weight
	its speed
	its mass
	its direction

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.

Which of the following will increase the mechanical advantage of this inclined plane?

59% Answer Correctly

	increase the force acting at the blue arrow
	lower the force acting at the blue arrow
	shorten the ramp
	lengthen the ramp

Solution

The mechanical advantage (MA) of an inclined plane is the effort distance divided by the resistance distance. In order to increase mechanical advantage, this ratio must increase which means making the effort distance longer and this can be accomplished by lengthening the length of the ramp.