ASVAB Mechanical Comprehension Practice Test 345906 Results

Your Results Global Average
Questions 5 5
Correct 0 2.95
Score 0% 59%

Review

1

Force of friction due to kinetic friction is __________ the force of friction due to static friction.

40% Answer Correctly

higher than

the same as

lower than

opposite


Solution

The formula for force of friction (Ff) is the same whether kinetic or static friction applies: Ff = μFN. To distinguish between kinetic and static friction, μk and μs are often used in place of μ.


2

The mechanical advantage of a block and tackle is equal to which of the following?

69% Answer Correctly

the number of loads

the number of input forces

the number of connecting ropes

the number of pulleys


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

A wedge is most similar to what other type of simple machine?

70% Answer Correctly

second-class lever

inclined plane

third-class lever

first-class lever


Solution

The wedge is a moving inclined plane that is used to lift, hold, or break apart an object. A wedge converts force applied to its blunt end into force perpendicular to its inclined surface. In contrast to a stationary plane where force is applied to the object being moved, with a wedge the object is stationary and the force is being applied to the plane. Examples of a wedge include knives and chisels.


4

What's the first gear in a gear train called?

57% Answer Correctly

input gear

idler gear

driven gear

driver gear


Solution

A gear train is two or more gears linked together. Gear trains are designed to increase or reduce the speed or torque outpout of a rotating system or change the direction of its output. The first gear in the chain is called the driver and the last gear in the chain the driven gear with the gears between them called idler gears.


5

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

61% Answer Correctly

decrease, increase

increase, increase

increase, decrease

decrease, decrease


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.