ASVAB Mechanical Comprehension Practice Test 433915 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.15
Score	0%	63%

Review

1 What is the mechanical advantage of this inclined plane if the length of the ramp is 18 ft. and the height of the green box is 2 ft.?

82% Answer Correctly

	4
	15
	9
	27

Solution

The mechanical advantage (MA) of an inclined plane is the effort distance divided by the resistance distance. In this case, the effort distance is the length of the ramp and the resistance distance is the height of the green box:

MA = \( \frac{d_e}{d_r} \) = \( \frac{18 ft.}{2 ft.} \) = 9

The measure of how much of the power put into a machine is turned into movement or force is called:

56% Answer Correctly

	force multiplication
	efficiency
	power
	mechanical advantage

Solution

The efficiency of a machine describes how much of the power put into the machine is turned into movement or force. A 100% efficient machine would turn all of the input power into output movement or force. However, no machine is 100% efficient due to friction, heat, wear and other imperfections that consume input power without delivering any output.

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

54% Answer Correctly

	its mass
	its weight
	its direction
	its speed

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.

Normal force is generally equal to the __________ of an object.

61% Answer Correctly

	mass
	weight
	coefficient of friction
	density

Solution

Normal force arises on a flat horizontal surface in response to an object's weight pressing it down. Consequently, normal force is generally equal to the object's weight.

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?

63% Answer Correctly

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

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.