ASVAB Mechanical Comprehension Practice Test 364614 Results

Your Results Global Average
Questions 5 5
Correct 0 3.20
Score 0% 64%

Review

1

A box is resting on a smooth floor. Static friction is present:

59% Answer Correctly

when an attempt is made to move the box

at all times

if the coefficient of friction is greater than one

only if normal force is present
Solution

For any given surface, the coefficient of static friction is higher than the coefficient of kinetic friction. More force is required to initally get an object moving than is required to keep it moving. Additionally, static friction only arises in response to an attempt to move an object (overcome the normal force between it and the surface).

2

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

81% Answer Correctly

kinetic energy

inertia

weight

mass
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.

3 If the handles of a wheelbarrow are 2.5 ft. from the wheel axle and the load is concentrated at a point 1.5 ft. from the axle, how many pounds of load will a 110 lbs. force lift?
47% Answer Correctly
66
183.3
29.3
165
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 resistance force:
\( F_r = \frac{F_e d_e}{d_r} \)
\( F_r = \frac{110 \times 2.5}{1.5} \)
\( F_r = \frac{275.0}{1.5} \)
\( F_r = 183.3 \)
4

What is work?

60% Answer Correctly

The potential for exertion

The movement of an object by a force

Force per unit time

Force per unit distance
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. By definition, work is the displacement of an object resulting from applied force.

5 A = 6 ft., the green box weighs 40 lbs., and the blue box weighs 60 lbs. What does distance B need to be for this lever to balance?
64% Answer Correctly
6 ft.
2 ft.
1 ft.
4 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:

40 lbs. x 6 ft. = 60 lbs. x dB

dB = \( \frac{40 \times 6 ft⋅lb}{60 lbs.} \) = \( \frac{240 ft⋅lb}{60 lbs.} \) = 4 ft.