ASVAB Mechanical Comprehension Practice Test 754390 Results

Your Results Global Average
Questions 5 5
Correct 0 3.14
Score 0% 63%

Review

1

The science that deals with motion and the forces that produce motion is called which of the following?

57% Answer Correctly

mechanics

engineering

aeronautics

physics


Solution

Mechanics deals with motion and the forces that produce motion.


2

Which of the following will increase the mechanical advantage of this inclined plane?

58% Answer Correctly

lengthen the ramp

shorten the ramp

increase the force acting at the blue arrow

lower the force acting at the blue arrow


Solution

The mechanical advantage (MA) of an inclined plane is the effort distance divided by the resistance distance. In order to increase mechanical advantage, this ratio must increase which means making the effort distance longer and this can be accomplished by lengthening the length of the ramp.


3 If the green box weighs 70 lbs. and is 1 ft. from the fulcrum, how far from the fulcrum would a 65 lbs. force need to be applied to balance the lever?
58% Answer Correctly
0 ft.
1.08 ft.
0.27 ft.
3.23 ft.

Solution

To balance this lever the torques at the green box and the blue arrow must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:

Rada = Rbdb

where a represents the green box and b the blue arrow, R is resistance (weight/force) and d is the distance from the fulcrum.

Solving for db, our missing value, and plugging in our variables yields:

db = \( \frac{R_ad_a}{R_b} \) = \( \frac{70 lbs. \times 1 ft.}{65 lbs.} \) = \( \frac{70 ft⋅lb}{65 lbs.} \) = 1.08 ft.


4

Which of these is the formula for kinetic energy?

67% Answer Correctly

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

\(KE = mgh\)

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

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


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.


5

Tension is a force that does which of the following?

75% Answer Correctly

heats up an object

stretches an object

compacts an object

slows an object


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.