ASVAB Mechanical Comprehension Practice Test 893821 Results

Your Results Global Average
Questions 5 5
Correct 0 2.92
Score 0% 58%

Review

1

Which of the following will increase the mechanical advantage of this inclined plane?

59% Answer Correctly

lower the force acting at the blue arrow

lengthen the ramp

shorten the ramp

increase the force acting at the blue arrow


Solution

The mechanical advantage (MA) of an inclined plane is the effort distance divided by the resistance distance. In order to increase mechanical advantage, this ratio must increase which means making the effort distance longer and this can be accomplished by lengthening the length of the ramp.


2

Which of the following is the formula for hydraulic pressure?

58% Answer Correctly

P = F/A

P = FA

P = FA2

P = F/A2


Solution

Hydraulics is the transmission of force through the use of liquids. Liquids are especially suited for transferring force in complex machines because they compress very little and can occupy very small spaces. Hydraulic pressure is calculated by dividing force by the area over which it is applied: P = F/A where F is force in pounds, A is area in square inches, and the resulting pressure is in pounds per square inch (psi).


3 If the radius of the axle is 3 and the radius of the wheel is 8, what is the mechanical advantage of this wheel and axle configuration?
52% Answer Correctly
0.38
3
2.67
8

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 8 and the output radius (where the resistance is being applied) is 3 for a mechanical advantage of \( \frac{8}{3} \) = 2.67


4 If the force applied at the blue arrow over 7 ft. moves the green box 1.17 ft., what is the mechanical advantage of this lever?
56% Answer Correctly
6
2
9
3

Solution

Mechanical advantage (MA) can be calculated knowing only the distance the effort (blue arrow) moves and the distance the resistance (green box) moves. The equation is:

MA = \( \frac{E_d}{R_d} \)

where Ed is the effort distance and Rd is the resistance distance. For this problem, the equation becomes:

MA = \( \frac{7 ft.}{1.17 ft.} \) = 6

You might be wondering how having an effort distance of 6 times the resistance distance is an advantage. Remember the principle of moments. For a lever in equilibrium the effort torque equals the resistance torque. Because torque is force x distance, if the effort distance is 6 times the resistance distance, the effort force must be \( \frac{1}{6} \) the resistance force. You're trading moving 6 times the distance for only having to use \( \frac{1}{6} \) the force.


5

What type of load varies with time or affects a structure that experiences a high degree of movement?

66% Answer Correctly

concentrated load

static load

impact 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.