ASVAB Mechanical Comprehension Practice Test 701295 Results

Your Results Global Average
Questions 5 5
Correct 0 2.82
Score 0% 56%

Review

1 If the handles of a wheelbarrow are 1.0 ft. from the wheel axle and the load is concentrated at a point 1.0 ft. from the axle, how many pounds of load will a 260 lbs. force lift?
47% Answer Correctly
274
260
0
30.2
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:
\( F_r = \frac{F_e d_e}{d_r} \)
\( F_r = \frac{260 \times 1.0}{1.0} \)
\( F_r = \frac{260.0}{1.0} \)
\( F_r = 260 \)
2

A fixed pulley is useful for which of the following?

53% Answer Correctly

multiplying the input distance

changing the direction of the input force

multiplying the input force

changing the direction of the output force
Solution

A fixed pulley is used to change the direction of a force and does not multiply the force applied. As such, it has a mechanical advantage of one. The benefit of a fixed pulley is that it can allow the force to be applied at a more convenient angle, for example, pulling downward or horizontally to lift an object instead of upward.

3

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

61% Answer Correctly

mass

weight

coefficient of friction

density
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.

4

Which of the following is not a type of bridge?

74% Answer Correctly

block

arch

cable

truss
Solution

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

5

Which class of lever offers no mechanical advantage?

45% Answer Correctly

first

third

second

none of these, all levers offer mechanical advantage
Solution

A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers.