ASVAB Mechanical Comprehension Practice Test 630773 Results

Your Results Global Average
Questions 5 5
Correct 0 3.08
Score 0% 62%

Review

1 If the handles of a wheelbarrow are 1.5 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 200 lbs. force lift?
47% Answer Correctly
300
227.5
41.3
200
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:
\( F_r = \frac{F_e d_e}{d_r} \)
\( F_r = \frac{200 \times 1.5}{1.5} \)
\( F_r = \frac{300.0}{1.5} \)
\( F_r = 200 \)
2 If you lift a 49 lbs. rock 4 ft. from the ground, how much work have you done?
71% Answer Correctly
196 ft⋅lb
0 ft⋅lb
53 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:
\( W = F \times d \)
\( W = 49 \times 4 \)
\( W = 196 \)
3

Which of the following is not a type of structural load?

49% Answer Correctly

occupancy load

dead load

live load

wind load
Solution

Dead load is the weight of the building and materials, live load is additional weight due to occupancy or use, snow load is the weight of accumulated snow on a structure and wind load is the force of wind pressures against structure surfaces.

4

The force amplification achieved by using a tool, mechanical device or machine system is called:

80% Answer Correctly

efficiency

mechanical advantage

work

power
Solution

Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Such a device utilizes input force and trades off forces against movement to amplify and/or change its direction.

5

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

59% Answer Correctly

if the coefficient of friction is greater than one

only if normal force is present

at all times

when an attempt is made to move the box
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).