ASVAB Mechanical Comprehension Practice Test 520335 Results

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

Review

1 How much work can a 3 hp engine do in 5 seconds?
52% Answer Correctly
12 ft⋅lb
6 ft⋅lb
8250 ft⋅lb
0 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:
\( W = 3 hp \times 550 \frac{ft⋅lb}{s} \times 5s = 8250 ft⋅lb \)
2

An inclined plane increases ___________ to reduce ____________.

58% Answer Correctly

force, distance

force, power

distance, force

distance, power
Solution

An inclined plane is a simple machine that reduces the force needed to raise an object to a certain height. Work equals force x distance and, by increasing the distance that the object travels, an inclined plane reduces the force necessary to raise it to a particular height. In this case, the mechanical advantage is to make the task easier. An example of an inclined plane is a ramp.

3 A mass of air has a pressure of 6.0 psi and a volume of 30 ft.3. If the air is compressed to a new volume of 10 ft.3, what is the new pressure?
56% Answer Correctly
20 psi
27 psi
36 psi
18 psi
Solution

According to Boyle's Law, pressure and volume are inversely proportional:

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

In this problem, V2 = 10 ft.3, V1 = 30 ft.3 and P1 = 6.0 psi. Solving for P2:

P2 = \( \frac{P_1}{\frac{V_2}{V_1}} \) = \( \frac{6.0 psi}{\frac{10 ft.^3}{30 ft.^3}} \) = 18 psi

4 A = 5 ft., the green box weighs 30 lbs., and the blue box weighs 40 lbs. What does distance B need to be for this lever to balance?
65% Answer Correctly
8 ft.
7.5 ft.
6 ft.
3.75 ft.
Solution
In order for this lever to balance, the torque acting on side A must equal the torque acting on side B. Torque is weight x distance from the fulcrum which means that the following must be true for the lever to balance:

fAdA = fBdB

For this problem, the equation becomes:

30 lbs. x 5 ft. = 40 lbs. x dB

dB = \( \frac{30 \times 5 ft⋅lb}{40 lbs.} \) = \( \frac{150 ft⋅lb}{40 lbs.} \) = 3.75 ft.

5

Which of these is the formula for kinetic energy?

67% Answer Correctly

\(KE = {m \over v^2 }\)

\(KE = mgh\)

\(KE = {1 \over 2}mv^2\)

\(KE = {1 \over 2}mh^2\)
Solution

Kinetic energy is the energy of movement and is a function of the mass of an object and its speed: \(KE = {1 \over 2}mv^2\) where m is mass in kilograms, v is speed in meters per second, and KE is in joules. The most impactful quantity to kinetic energy is velocity as an increase in mass increases KE linearly while an increase in speed increases KE exponentially.