ASVAB Mechanical Comprehension Practice Test 154941 Results

Your Results Global Average
Questions 5 5
Correct 0 2.96
Score 0% 59%

Review

1 If A = 9 ft., B = 2 ft., C = 5 ft., the green box weighs 50 lbs. and the blue box weighs 55 lbs., what does the orange box have to weigh for this lever to balance?
43% Answer Correctly
68 lbs.
0 lbs.
22.67 lbs.
450 lbs.
Solution
In order for this lever to balance, the torque acting on each side of the fulrum must be equal. So, the torque produced by A must equal the torque produced by B and C. Torque is weight x distance from the fulcrum which means that the following must be true for the lever to balance:

fAdA = fBdB + fCdC

For this problem, this equation becomes:

50 lbs. x 9 ft. = 55 lbs. x 2 ft. + fC x 5 ft.

450 ft. lbs. = 110 ft. lbs. + fC x 5 ft.

fC = \( \frac{450 ft. lbs. - 110 ft. lbs.}{5 ft.} \) = \( \frac{340 ft. lbs.}{5 ft.} \) = 68 lbs.

2

Normal force is generally equal to the __________ of an object.

61% Answer Correctly

density

coefficient of friction

weight

mass
Solution

Normal force arises on a flat horizontal surface in response to an object's weight pressing it down. Consequently, normal force is generally equal to the object's weight.

3 A mass of air has a pressure of 12.0 psi and a volume of 60 ft.3. If the air is compressed to a new volume of 45 ft.3, what is the new pressure?
56% Answer Correctly
16 psi
14.4 psi
5.3 psi
25 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 = 45 ft.3, V1 = 60 ft.3 and P1 = 12.0 psi. Solving for P2:

P2 = \( \frac{P_1}{\frac{V_2}{V_1}} \) = \( \frac{12.0 psi}{\frac{45 ft.^3}{60 ft.^3}} \) = 16 psi

4

Which of the following is not a type of bridge?

74% Answer Correctly

cable

truss

arch

block
Solution

The six basic bridge forms are beam, truss, arch, cantilever, cable, and suspension.

5

What is the first step to solving a problem where multiple forces are acting on an object?

61% Answer Correctly

calculate the total force

calculate kinetic energy

calculate the net force

calculate potential energy
Solution

In mechanics, multiple forces are often acting on a particular object and, taken together, produce the net force acting on that object. Like force, net force is a vector quantity in that it has magnitude and direction.