ASVAB Mechanical Comprehension Practice Test 132037 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.61
Score	0%	52%

Review

The advantage of using a third-class lever is that it increases:

37% Answer Correctly

	the distance traveled by the load
	the mechanical advantage of the lever
	the force applied to the load
	the speed of the load

Solution

A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers.

The work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. This defines which of the following?

60% Answer Correctly

	conservation of mechanical energy
	work-energy theorem
	Pascal's law
	mechanical advantage

Solution

The work-energy theorem states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. Simply put, work imparts kinetic energy to the matter upon which the work is being done.

Which of the following is not a characteristic of a ceramic?

61% Answer Correctly

	low density
	chemically stable
	high melting point
	low corrosive action

Solution

Ceramics are mixtures of metallic and nonmetallic elements that withstand exteme thermal, chemical, and pressure environments. They have a high melting point, low corrosive action, and are chemically stable. Examples include rock, sand, clay, glass, brick, and porcelain.

4 If A = 10 ft., B = 1 ft., C = 5 ft., the green box weighs 45 lbs. and the blue box weighs 55 lbs., what does the orange box have to weigh for this lever to balance?

44% Answer Correctly

	316 lbs.
	0 lbs.
	4 lbs.
	79 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:

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

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

f_C = \( \frac{450 ft. lbs. - 55 ft. lbs.}{5 ft.} \) = \( \frac{395 ft. lbs.}{5 ft.} \) = 79 lbs.

The science that deals with motion and the forces that produce motion is called which of the following?

57% Answer Correctly

	mechanics
	aeronautics
	physics
	engineering

Solution

Mechanics deals with motion and the forces that produce motion.