ASVAB Mechanical Comprehension Practice Test 460563 Results

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

Review

Sam can do 50 ft. lb. of work in 2 minutes and 5 seconds. What would Sam have to do to increase his power output?

64% Answer Correctly

	do the work in 3 minutes
	do the work in 2 minutes
	do 25 ft. lb. of work in 2 minutes 5 seconds
	do 100 ft. lb. of work in 4 minutes 12 seconds

Solution

Power is the rate of doing work or \(\frac{W}{t}\). To increase power, increase the work being done in the same amount of time or do the same amount of work in less time.

What type of load doesn't create specific stress points or vary with time?

60% Answer Correctly

	static uniformly distributed load
	non-uniformly distributed load
	concentrated load
	impact 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.

The mechanical advantage of a wheel and axle is equal to the:

61% Answer Correctly

	ratio of the diameters of the wheels
	difference in the diameters of the wheels
	length of the axle
	difference in the lengths of the axles

Solution

A wheel and axle uses two different diameter wheels mounted to a connecting axle. Force is applied to the larger wheel and large movements of this wheel result in small movements in the smaller wheel. Because a larger movement distance is being translated to a smaller distance, force is increased with a mechanical advantage equal to the ratio of the diameters of the wheels. An example of a wheel and axle is the steering wheel of a car.

4 What is the efficiency of a machine has work input of 205 ft⋅lb and work output of 164 ft⋅lb?

67% Answer Correctly

	160%
	0%
	80%
	40%

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:
\( Efficiency = \frac{Work_{out}}{Work_{in}} \times 100 \) \( = \frac{164 ft⋅lb}{205 ft⋅lb} \times 100 \) \( = 80% \) %

When it comes to force, mass and acceleration have what kind of relationship?

66% Answer Correctly

	linear
	exponential
	inverse
	logarithmic

Solution

Newton's Second Law of Motion states that "The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object." This Law describes the linear relationship between mass and acceleration when it comes to force and leads to the formula F = ma or force equals mass multiplied by rate of acceleration.