ASVAB Mechanical Comprehension Practice Test 415864 Results

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

Review

What type of load creates different stresses at different locations on a structure?

60% Answer Correctly

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

The mass of an object correlates to the size of the object but ultimately depends on:

67% Answer Correctly

	gravity
	the object's density
	the object's weight
	the object's potential energy

Solution

Mass is a measure of the amount of matter in an object. In general, larger objects have larger mass than smaller objects but mass ultimately depends on how compact (dense) a substance is.

3 If A = 12 ft., B = 2 ft., C = 11 ft., the green box weighs 35 lbs. and the blue box weighs 50 lbs., what does the orange box have to weigh for this lever to balance?

44% Answer Correctly

	0 lbs.
	420 lbs.
	17 lbs.
	29.09 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:

35 lbs. x 12 ft. = 50 lbs. x 2 ft. + f_C x 11 ft.

420 ft. lbs. = 100 ft. lbs. + f_C x 11 ft.

f_C = \( \frac{420 ft. lbs. - 100 ft. lbs.}{11 ft.} \) = \( \frac{320 ft. lbs.}{11 ft.} \) = 29.09 lbs.

4 What is the mechanical advantage of this inclined plane if the length of the ramp is 30 ft. and the height of the green box is 6 ft.?

82% Answer Correctly

	4.5
	5
	15
	10

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 = \( \frac{d_e}{d_r} \) = \( \frac{30 ft.}{6 ft.} \) = 5

A box is resting on a smooth floor. Static friction is present:

59% Answer Correctly

	when an attempt is made to move the box
	only if normal force is present
	at all times
	if the coefficient of friction is greater than one

Solution

For any given surface, the coefficient of static friction is higher than the coefficient of kinetic friction. More force is required to initally get an object moving than is required to keep it moving. Additionally, static friction only arises in response to an attempt to move an object (overcome the normal force between it and the surface).