ASVAB Mechanical Comprehension Practice Test 776724 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.29
Score	0%	66%

Review

1 If A = 10 ft., B = 1 ft., C = 5 ft., the green box weighs 50 lbs. and the blue box weighs 55 lbs., what does the orange box have to weigh for this lever to balance?

44% Answer Correctly

	22.25 lbs.
	29.67 lbs.
	267 lbs.
	89 lbs.

Solution

In order for this lever to balance, the torque acting on each side of the fulrum must be equal. So, the torque produced by A must equal the torque produced by B and C. 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 + f_Cd_C

For this problem, this equation becomes:

50 lbs. x 10 ft. = 55 lbs. x 1 ft. + f_C x 5 ft.

500 ft. lbs. = 55 ft. lbs. + f_C x 5 ft.

f_C = \( \frac{500 ft. lbs. - 55 ft. lbs.}{5 ft.} \) = \( \frac{445 ft. lbs.}{5 ft.} \) = 89 lbs.

What's the first gear in a gear train called?

57% Answer Correctly

	input gear
	idler gear
	driven gear
	driver gear

Solution

A gear train is two or more gears linked together. Gear trains are designed to increase or reduce the speed or torque outpout of a rotating system or change the direction of its output. The first gear in the chain is called the driver and the last gear in the chain the driven gear with the gears between them called idler gears.

Potential energy is energy that has the potential to be converted into what?

80% Answer Correctly

	work
	heat
	kinetic energy
	power

Solution

Potential energy is the energy of an object by virtue of its position relative to other objects. It is energy that has the potential to be converted into kinetic energy.

Which of the following statements about drag is false?

58% Answer Correctly

	drag occurs during movement through a fluid
	the amount of drag depends on the shape of an object
	the amount of drag depends on the speed of an object
	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.

The steering wheel of a car is an example of which type of simple machine?

88% Answer Correctly

	block and tackle
	first-class lever
	wheel and axle
	fixed pulley

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.