ASVAB Mechanical Comprehension Practice Test 313588 Results

Your Results Global Average
Questions 5 5
Correct 0 3.07
Score 0% 61%

Review

1

Specific gravity is a comparison of the density of an object with the density of:

57% Answer Correctly

water

carbon

oil

air
Solution

Specific gravity is the ratio of the density of equal volumes of a substance and water and is measured by a hyrdometer.

2

A watt is the unit for which of the following?

71% Answer Correctly

energy

work

power

mechanical advantage
Solution

Power is the rate at which work is done, P = w/t, or work per unit time. The watt (W) is the unit for power and is equal to 1 joule (or newton-meter) per second. Horsepower (hp) is another familiar unit of power used primarily for rating internal combustion engines. 1 hp equals 746 watts.

3

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

59% Answer Correctly

only if normal force is present

when an attempt is made to move the box

if the coefficient of friction is greater than one

at all times
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).

4

The standard unit of energy is the:

73% Answer Correctly

Watt

Horsepower

Joule

Volt
Solution

The Joule (J) is the standard unit of energy and has the unit \({kg \times m^2} \over s^2\).

5 If A = 11 ft., B = 1 ft., C = 9 ft., the green box weighs 35 lbs. and the blue box weighs 55 lbs., what does the orange box have to weigh for this lever to balance?
44% Answer Correctly
36.67 lbs.
35 lbs.
0 lbs.
12.22 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:

fAdA = fBdB + fCdC

For this problem, this equation becomes:

35 lbs. x 11 ft. = 55 lbs. x 1 ft. + fC x 9 ft.

385 ft. lbs. = 55 ft. lbs. + fC x 9 ft.

fC = \( \frac{385 ft. lbs. - 55 ft. lbs.}{9 ft.} \) = \( \frac{330 ft. lbs.}{9 ft.} \) = 36.67 lbs.