ASVAB Mechanical Comprehension Practice Test 955975 Results

Your Results Global Average
Questions 5 5
Correct 0 2.85
Score 0% 57%

Review

1 If the radius of the axle is 5 and the radius of the wheel is 10, what is the mechanical advantage of this wheel and axle configuration?
52% Answer Correctly
2.0
10
5
-5

Solution

The mechanical advantage of a wheel and axle is the input radius divided by the output radius:

MA = \( \frac{r_i}{r_o} \)

In this case, the input radius (where the effort force is being applied) is 10 and the output radius (where the resistance is being applied) is 5 for a mechanical advantage of \( \frac{10}{5} \) = 2.0


2

Two or more pulleys used together are called:

71% Answer Correctly

third-class lever

wheel and axle

gears

block and tackle


Solution

Two or more pulleys used together constitute a block and tackle which, unlike a fixed pulley, does impart mechanical advantage as a function of the number of pulleys that make up the arrangement.  So, for example, a block and tackle with three pulleys would have a mechanical advantage of three.


3

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

62% Answer Correctly

density

weight

mass

coefficient of friction


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

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

37% Answer Correctly

the force applied to the load

the speed of 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.


5

Two gears are connected and the larger gear drives the smaller gear. The speed of rotation will __________ and the torque will __________.

61% Answer Correctly

decrease, increase

increase, decrease

decrease, decrease

increase, increase


Solution

Connected gears of different numbers of teeth are used together to change the rotational speed and torque of the input force. If the smaller gear drives the larger gear, the speed of rotation will be reduced and the torque will increase. If the larger gear drives the smaller gear, the speed of rotation will increase and the torque will be reduced.