ASVAB Mechanical Comprehension Practice Test 715056 Results

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

Review

1

A box is resting on a smooth floor. Static friction is present:

59% Answer Correctly

if the coefficient of friction is greater than one

at all times

when an attempt is made to move the box

only if normal force is present


Solution

For any given surface, the coefficient of static friction is higher than the coefficient of kinetic friction. More force is required to initally get an object moving than is required to keep it moving. Additionally, static friction only arises in response to an attempt to move an object (overcome the normal force between it and the surface).


2

A shovel is an example of which class of lever?

56% Answer Correctly

a shovel is not a lever

second

third

first


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.


3

A fixed pulley is useful for which of the following?

54% Answer Correctly

changing the direction of the input force

changing the direction of the output force

multiplying the input distance

multiplying the input 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.


4

A fixed pulley has a mechanical advantage of:

68% Answer Correctly

1

-1

0

2


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.


5

Which of the following is not a modulus of elasticity?

47% Answer Correctly

shear modulus

stretch modulus

bulk modulus

stress modulus


Solution

The modulus of elasticity measures how much a material or structure will deflect under stress. Stretch modulus is longitudinal stretch (like stretching raw bread dough), shear modulus is longitudinal deflection (like the horizontal displacement of a stack of magzines when a heavy object is placed upon them), and bulk modulus is compression of volume (like the compression of a loaf of bread under a heavy can at the bottom of a grocery bag).