ASVAB Mechanical Comprehension Practice Test 537819 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.68
Score	0%	54%

Review

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

53% Answer Correctly

	8250 ft⋅lb
	1 ft⋅lb
	0 ft⋅lb
	6 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:
\( W = 3 hp \times 550 \frac{ft⋅lb}{s} \times 5s = 8250 ft⋅lb \)

Which of the following is not a type of structural load?

49% Answer Correctly

	wind load
	occupancy load
	live load
	dead load

Solution

Dead load is the weight of the building and materials, live load is additional weight due to occupancy or use, snow load is the weight of accumulated snow on a structure and wind load is the force of wind pressures against structure surfaces.

3 If the handles of a wheelbarrow are 2.5 ft. from the wheel axle, how many pounds of force must you exert to lift the handles if it's carrying a 250 lbs. load concentrated at a point 1.5 ft. from the axle?

52% Answer Correctly

	-59
	375
	66.7
	150

Solution

This problem describes a second-class lever and, for a second class lever, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance: F_ed_e = F_rd_r. In this problem we're looking for effort force:
\( F_e = \frac{F_r d_r}{d_e} \)
\( F_e = \frac{250 \times 1.5}{2.5} \)
\( F_e = \frac{375.0}{2.5} \)
\( F_e = 150 \)

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

59% Answer Correctly

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

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.

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

54% Answer Correctly

	its speed
	its direction
	its weight
	its mass

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.