ASVAB Mechanical Comprehension Practice Test 391351 Results

Your Results Global Average
Questions 5 5
Correct 0 3.25
Score 0% 65%

Review

1

Two or more pulleys used together are called:

71% Answer Correctly

gears

third-class lever

block and tackle

wheel and axle


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.


2 If the green box weighs 10 lbs. and is 1 ft. from the fulcrum, how far from the fulcrum would a 65 lbs. force need to be applied to balance the lever?
58% Answer Correctly
0.08 ft.
0.15 ft.
0.04 ft.
0.05 ft.

Solution

To balance this lever the torques at the green box and the blue arrow must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:

Rada = Rbdb

where a represents the green box and b the blue arrow, R is resistance (weight/force) and d is the distance from the fulcrum.

Solving for db, our missing value, and plugging in our variables yields:

db = \( \frac{R_ad_a}{R_b} \) = \( \frac{10 lbs. \times 1 ft.}{65 lbs.} \) = \( \frac{10 ft⋅lb}{65 lbs.} \) = 0.15 ft.


3

What type of load creates different stresses at different locations on a structure?

60% Answer Correctly

impact load

non-uniformly distributed load

static uniformly distributed load

dynamic 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.


4

What type of load acts on a relatively small area of a structure?

75% Answer Correctly

dynamic load

non-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

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

61% Answer Correctly

ratio of the diameters of the wheels

difference in the diameters of the wheels

difference in the lengths of the axles

length of the axle


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.