ASVAB Mechanical Comprehension Practice Test 834621 Results

Your Results Global Average
Questions 5 5
Correct 0 3.19
Score 0% 64%

Review

1

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

59% Answer Correctly

when an attempt is made to move the box

at all times

only if normal force is present

if the coefficient of friction is greater than one


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

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 connecting ropes

the number of input forces

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 If you lift a 17 lbs. rock 22 ft. from the ground, how much work have you done?
71% Answer Correctly
39 ft⋅lb
1 ft⋅lb
None of these is correct
374 ft⋅lb

Solution
Work is force times distance. In this case, the force is the weight of the rock so:
\( W = F \times d \)
\( W = 17 \times 22 \)
\( W = 374 \)

4

What type of load doesn't create specific stress points or vary with time?

60% Answer Correctly

non-uniformly distributed load

static uniformly distributed load

concentrated load

impact load


Solution

A concentrated load acts on a relatively small area of a structure, a static uniformly distributed load doesn't create specific stress points or vary with time, a dynamic load varies with time or affects a structure that experiences a high degree of movement, an impact load is sudden and for a relatively short duration and a non-uniformly distributed load creates different stresses at different locations on a structure.


5

Which of the following is not a characteristic of a ceramic?

61% Answer Correctly

chemically stable

low density

high melting point

low corrosive action


Solution

Ceramics are mixtures of metallic and nonmetallic elements that withstand exteme thermal, chemical, and pressure environments. They have a high melting point, low corrosive action, and are chemically stable. Examples include rock, sand, clay, glass, brick, and porcelain.