ASVAB Mechanical Comprehension Practice Test 350728 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.18
Score	0%	64%

Review

Which of the following statements about drag is false?

58% Answer Correctly

	drag occurs during movement through a fluid
	slower objects experience more drag than faster objects
	the amount of drag depends on the speed of an object
	the amount of drag depends on the shape of an object

Solution

Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area.

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

60% Answer Correctly

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

3 If A = 3 ft. and the green box weighs 10 lbs. what is the torque acting on the A side of this lever?

74% Answer Correctly

	15 ft⋅lb
	0 ft⋅lb
	90 ft⋅lb
	30 ft⋅lb

Solution

For a lever, torque is weight x distance from the fulcrum which, in this case, is: 10 ft. x 3 lbs. = 30 ft⋅lb

4 If 10 lbs. of force is applied 7 ft. from the fulcrum at the blue arrow and the green box is 3 ft. from the fulcrum, how much would the green box have to weigh to balance the lever?

62% Answer Correctly

	7.78 lbs.
	11.67 lbs.
	23.33 lbs.
	46.67 lbs.

Solution

To balance this lever the torques at the green box and the blue arrow must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:

R_ad_a = R_bd_b

where a represents the green box and b the blue arrow, R is resistance (weight/force) and d is the distance from the fulcrum.

Solving for R_a, our missing value, and plugging in our variables yields:

R_a = \( \frac{R_bd_b}{d_a} \) = \( \frac{10 lbs. \times 7 ft.}{3 ft.} \) = \( \frac{70 ft⋅lb}{3 ft.} \) = 23.33 lbs.

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.