ASVAB Mechanical Comprehension Practice Test 729319 Results

Your Results Global Average
Questions 5 5
Correct 0 2.69
Score 0% 54%

Review

1

The advantage of using a third-class lever is that it increases:

37% Answer Correctly

the speed of the load

the force applied to the load

the mechanical advantage of the lever

the distance traveled by the load
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.

2

Which of the following represents the force a surface exerts when an object presses against it?

48% Answer Correctly

counter force

normal force

friction

mass
Solution

Normal force (FN) represents the force a surface exerts when an object presses against it.

3

The standard unit of energy is the:

72% Answer Correctly

Watt

Volt

Horsepower

Joule
Solution

The Joule (J) is the standard unit of energy and has the unit \({kg \times m^2} \over s^2\).

4

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

60% Answer Correctly

difference in the diameters of the wheels

ratio of the diameters of the wheels

length of the axle

difference in the lengths of the axles
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.

5 How much work can a 7 hp engine do in 3 seconds?
52% Answer Correctly
14 ft⋅lb
2 ft⋅lb
0 ft⋅lb
11550 ft⋅lb
Solution
Horsepower (hp) is a common measure of power output for complex machines. By definition, a 1 hp machine does 550 ft⋅lb of work in 1 second: 1 hp = 550 ft⋅lb/s. Substituting the variables for this problem gives us:
\( W = 7 hp \times 550 \frac{ft⋅lb}{s} \times 3s = 11550 ft⋅lb \)