ASVAB Mechanical Comprehension Practice Test 275816 Results

Your Results Global Average
Questions 5 5
Correct 0 2.95
Score 0% 59%

Review

1 What is the power output of a 4 hp engine that's 50% efficient?
40% Answer Correctly
1100 \( \frac{ft⋅lb}{s} \)
366.7 \( \frac{ft⋅lb}{s} \)
0 \( \frac{ft⋅lb}{s} \)
200 \( \frac{ft⋅lb}{s} \)
Solution
\( Efficiency = \frac{Power_{out}}{Power_{in}} \times 100 \)
Solving for power out: \( P_{o} = \frac{E \times P_{i}}{100} \)
Knowing that 1 hp = 550 \( \frac{ft⋅lb}{s} \), Pi becomes 4 hp x 550 \( \frac{ft⋅lb}{s} \) = 2200 \( \frac{ft⋅lb}{s} \)
\( P_{o} = \frac{E \times P_{i}}{100} = \frac{50 \times 2200 \frac{ft⋅lb}{s}}{100} \) \( = \frac{110000 \frac{ft⋅lb}{s}}{100} \) = 1100 \( \frac{ft⋅lb}{s} \)
2

A screw is most like which of the following other simple machines?

50% Answer Correctly

inclined plane

block and tackle

wheel and axle

first-class lever
Solution

A screw is an inclined plane wrapped in ridges (threads) around a cylinder. The distance between these ridges defines the pitch of the screw and this distance is how far the screw advances when it is turned once. The mechanical advantage of a screw is its circumference divided by the pitch.

3 If the handles of a wheelbarrow are 1.5 ft. from the wheel axle, how many pounds of force must you exert to lift the handles if it's carrying a 110 lbs. load concentrated at a point 0.5 ft. from the axle?
52% Answer Correctly
36.7
0
32.2
330
Solution
This problem describes a second-class lever and, for a second class lever, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance: Fede = Frdr. In this problem we're looking for effort force:
\( F_e = \frac{F_r d_r}{d_e} \)
\( F_e = \frac{110 \times 0.5}{1.5} \)
\( F_e = \frac{55.0}{1.5} \)
\( F_e = 36.7 \)
4

An object's resistance to changes in direction is known as:

82% Answer Correctly

weight

mass

kinetic energy

inertia
Solution

The more mass a substance has the more force is required to move it or to change its direction. This resistance to changes in direction is known as inertia.

5

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

61% Answer Correctly

chemically stable

low density

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.