ASVAB Mechanical Comprehension Practice Test 679373 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.69
Score	0%	54%

Review

Lisa lifts a 25 pound box from the floor onto a loading dock 4 ft. off the ground. Sam slides the same box along a ramp to move it up another 4 ft. onto a flatbed truck. Who has done more work?

50% Answer Correctly

	Lisa
	They have done an equal amount of work
	Neither have done any work
	Sam

Solution

Work is force multiplied by distance. Because both Connie and Sam moved the same weight the same distance they have done an equal amount of work. Sam employed the mechnacial advantage of an inclined plane so he exerted less effort to do the work but the amount of work done was still the same.

Which of the following is the formula for gravitational potential energy?

61% Answer Correctly

	\(PE = mg^2h\)
	\(PE = { 1 \over 2} mv^2\)
	\(PE = { 1 \over 2} mg^2\)
	\(PE = mgh\)

Solution

Gravitational potential energy is energy by virtue of gravity. The higher an object is raised above a surface the greater the distance it must fall to reach that surface and the more velocity it will build as it falls. For gravitational potential energy, PE = mgh where m is mass (kilograms), h is height (meters), and g is acceleration due to gravity which is a constant (9.8 m/s²).

Depending on where you apply effort and resistance, the wheel and axle can multiply:

45% Answer Correctly

	force or distance
	force or speed
	speed or power
	power or distance

Solution

If you apply the resistance to the axle and the effort to the wheel, the wheel and axle will multiply force and if you apply the resistance to the wheel and the effort to the axle, it will multiply speed.

What type of load creates different stresses at different locations on a structure?

60% Answer Correctly

	impact load
	dynamic load
	static uniformly distributed load
	non-uniformly distributed load

Solution

A concentrated load acts on a relatively small area of a structure, a static uniformly distributed load doesn't create specific stress points or vary with time, a dynamic load varies with time or affects a structure that experiences a high degree of movement, an impact load is sudden and for a relatively short duration and a non-uniformly distributed load creates different stresses at different locations on a structure.

5 How much work can a 3 hp engine do in 9 seconds?

52% Answer Correctly

	12 ft⋅lb
	1 ft⋅lb
	0 ft⋅lb
	14850 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:
\( W = 3 hp \times 550 \frac{ft⋅lb}{s} \times 9s = 14850 ft⋅lb \)