ASVAB Mechanical Comprehension Practice Test 688663 Results

Your Results Global Average
Questions 5 5
Correct 0 3.10
Score 0% 62%

Review

1 How much work can a 1 hp engine do in 9 seconds?
52% Answer Correctly
0 ft⋅lb
9 ft⋅lb
4950 ft⋅lb
2 ft⋅lb
Solution
Horsepower (hp) is a common measure of power output for complex machines. By definition, a 1 hp machine does 550 ft⋅lb of work in 1 second: 1 hp = 550 ft⋅lb/s. Substituting the variables for this problem gives us:
\( W = 1 hp \times 550 \frac{ft⋅lb}{s} \times 9s = 4950 ft⋅lb \)
2 70 lbs. of effort is used by a machine to lift a 630 lbs. box. What is the mechanical advantage of the machine?
84% Answer Correctly
9
9.9
10.5
13.5
Solution

Mechanical advantage is resistance force divided by effort force:

MA = \( \frac{F_r}{F_e} \) = \( \frac{630 lbs.}{70 lbs.} \) = 9

3

Two or more pulleys used together are called:

71% Answer Correctly

wheel and axle

gears

third-class lever

block and tackle
Solution

Two or more pulleys used together constitute a block and tackle which, unlike a fixed pulley, does impart mechanical advantage as a function of the number of pulleys that make up the arrangement.  So, for example, a block and tackle with three pulleys would have a mechanical advantage of three.

4

A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?

50% Answer Correctly

in the middle

tension is equal in all parts of the rope

near the truck

near the car
Solution

Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress.

5

Boyle's law defines the relationship between pressure and volume as:

57% Answer Correctly

\(\frac{P_1}{P_2} = {V_1}{V_2}\)

\(\frac{P_1}{P_2} = \frac{V_2}{V_1}\)

\(\frac{P_1}{P_2} = \frac{V_1}{V_2}\)

\({P_1}{P_2} = {V_1}{V_2}\)
Solution

Boyle's law states that "for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional". Expressed as a formula, that's \(\frac{P_1}{P_2} = \frac{V_2}{V_1}\)