ASVAB Mechanical Comprehension Practice Test 929172 Results

Your Results Global Average
Questions 5 5
Correct 0 3.01
Score 0% 60%

Review

1

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

66% Answer Correctly

impact load

dynamic load

static load

concentrated 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.


2 What's the mechanical advantage of a wedge that's 3 inches wide and 6 inches long?
83% Answer Correctly
6
2
3
5

Solution

The mechanical advantage (MA) of a wedge is its length divided by its thickness:

MA = \( \frac{l}{t} \) = \( \frac{6 in.}{3 in.} \) = 2


3 If the radius of the axle is 5 and the radius of the wheel is 6, what is the mechanical advantage of this wheel and axle configuration?
52% Answer Correctly
5
1
-1
1.2

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 6 and the output radius (where the resistance is being applied) is 5 for a mechanical advantage of \( \frac{6}{5} \) = 1.2


4

A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?

50% Answer Correctly

in the middle

tension is equal in all parts of the rope

near the truck

near the car


Solution

Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress.


5 If the handles of a wheelbarrow are 0.5 ft. from the wheel axle, how many pounds of force must you exert to lift the handles if it's carrying a 230 lbs. load concentrated at a point 0.5 ft. from the axle?
52% Answer Correctly
-80
397.5
230
None of these is correct

Solution
This problem describes a second-class lever and, for a second class lever, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance: Fede = Frdr. In this problem we're looking for effort force:
\( F_e = \frac{F_r d_r}{d_e} \)
\( F_e = \frac{230 \times 0.5}{0.5} \)
\( F_e = \frac{115.0}{0.5} \)
\( F_e = 230 \)