ASVAB Mechanical Comprehension Practice Test 535568 Results

Your Results Global Average
Questions 5 5
Correct 0 3.28
Score 0% 66%

Review

1

An inclined plane increases ___________ to reduce ____________.

58% Answer Correctly

force, power

force, distance

distance, power

distance, force


Solution

An inclined plane is a simple machine that reduces the force needed to raise an object to a certain height. Work equals force x distance and, by increasing the distance that the object travels, an inclined plane reduces the force necessary to raise it to a particular height. In this case, the mechanical advantage is to make the task easier. An example of an inclined plane is a ramp.


2

If the handles of a wheelbarrow are 3 ft. from the wheel axle, what force must you exert to lift the handles if it's carrying a 270 lb. load concentrated at a point 0.5 ft. from the axle?

56% Answer Correctly

0.83 lbs

90 lbs

810 lbs

45 lbs


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. Plugging in the variables from this problem yields:

Fe x 3 ft. = 270 lbs x 0.5 ft
Fe = 135 ft-lb. / 3 ft 
F= 45 lbs


3

The mechanical advantage of a wheel and axle is equal to the:

61% Answer Correctly

ratio of the diameters of the wheels

length of the axle

difference in the lengths of the axles

difference in the diameters of the wheels


Solution

A wheel and axle uses two different diameter wheels mounted to a connecting axle. Force is applied to the larger wheel and large movements of this wheel result in small movements in the smaller wheel. Because a larger movement distance is being translated to a smaller distance, force is increased with a mechanical advantage equal to the ratio of the diameters of the wheels. An example of a wheel and axle is the steering wheel of a car.


4

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

82% Answer Correctly

inertia

kinetic energy

mass

weight


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.


5

According to Boyle's law, for a fixed amount of gas kept at a fixed temperature, which of the following are inversely proportional?

64% Answer Correctly

pressure, volume

volume, mass

density, volume

pressure, density


Solution

Boyle's law states that "for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional".