ASVAB Mechanical Comprehension Practice Test 863079 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.06
Score	0%	61%

Review

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

45% Answer Correctly

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

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.

A a seesaw / teeter-totter is an example of which of the following?

69% Answer Correctly

	second-class lever
	inclined plane
	first-class lever
	third-class lever

Solution

A first-class lever is used to increase force or distance while changing the direction of the force. The lever pivots on a fulcrum and, when a force is applied to the lever at one side of the fulcrum, the other end moves in the opposite direction. The position of the fulcrum also defines the mechanical advantage of the lever. If the fulcrum is closer to the force being applied, the load can be moved a greater distance at the expense of requiring a greater input force. If the fulcrum is closer to the load, less force is required but the force must be applied over a longer distance. An example of a first-class lever is a seesaw / teeter-totter.

A fixed pulley has a mechanical advantage of:

68% Answer Correctly

	2
	1
	0
	-1

Solution

A fixed pulley is used to change the direction of a force and does not multiply the force applied. As such, it has a mechanical advantage of one. The benefit of a fixed pulley is that it can allow the force to be applied at a more convenient angle, for example, pulling downward or horizontally to lift an object instead of upward.

Which of the following statements about drag is false?

58% Answer Correctly

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

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.

5 A = 8 ft., the green box weighs 30 lbs., and the blue box weighs 70 lbs. What does distance B need to be for this lever to balance?

65% Answer Correctly

	6.86 ft.
	0 ft.
	3.43 ft.
	8 ft.

Solution

In order for this lever to balance, the torque acting on side A must equal the torque acting on side B. Torque is weight x distance from the fulcrum which means that the following must be true for the lever to balance:

f_Ad_A = f_Bd_B

For this problem, the equation becomes:

30 lbs. x 8 ft. = 70 lbs. x d_B

d_B = \( \frac{30 \times 8 ft⋅lb}{70 lbs.} \) = \( \frac{240 ft⋅lb}{70 lbs.} \) = 3.43 ft.