ASVAB Mechanical Comprehension Practice Test 415562 Results

Your Results Global Average
Questions 5 5
Correct 0 3.25
Score 0% 65%

Review

1 If the green box weighs 60 lbs. and is 3 ft. from the fulcrum, how much weight would need to be placed at the blue arrow to balance the lever if the arrow's distance from the fulcrum is 2 ft.?
63% Answer Correctly
45 lbs.
30 lbs.
360 lbs.
90 lbs.

Solution

To balance this lever the torques on each side of the fulcrum must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:

Rada = Rbdb

where a represents the left side of the fulcrum and b the right, R is resistance (weight) and d is the distance from the fulcrum.

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

Rb = \( \frac{R_ad_a}{d_b} \) = \( \frac{60 lbs. \times 3 ft.}{2 ft.} \) = \( \frac{180 ft⋅lb}{2 ft.} \) = 90 lbs.


2

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

61% Answer Correctly

low density

chemically stable

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.


3

Tension is a force that does which of the following?

76% Answer Correctly

slows an object

stretches an object

heats up an object

compacts 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.


4

Assuming force applied remains constant, which of the following will result in more work being done?

53% Answer Correctly

moving the object farther

moving the object with more speed

increasing the coefficient of friction

moving the object with more acceleration


Solution

Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done.


5 If you lift a 19 lbs. rock 19 ft. from the ground, how much work have you done?
71% Answer Correctly
171 ft⋅lb
0 ft⋅lb
361 ft⋅lb
None of these is correct

Solution
Work is force times distance. In this case, the force is the weight of the rock so:
\( W = F \times d \)
\( W = 19 \times 19 \)
\( W = 361 \)