ASVAB Mechanical Comprehension Practice Test 170419 Results

Your Results Global Average
Questions 5 5
Correct 0 2.87
Score 0% 57%

Review

1

Lisa lifts a 25 pound box from the floor onto a loading dock 4 ft. off the ground. Sam slides the same box along a ramp to move it up another 4 ft. onto a flatbed truck. Who has done more work?

50% Answer Correctly

Lisa

Neither have done any work

They have done an equal amount of work

Sam


Solution

Work is force multiplied by distance. Because both Connie and Sam moved the same weight the same distance they have done an equal amount of work. Sam employed the mechnacial advantage of an inclined plane so he exerted less effort to do the work but the amount of work done was still the same.


2

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

60% Answer Correctly

concentrated load

non-uniformly distributed load

static uniformly distributed 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.


3

Which of the following is the formula for gravitational potential energy?

61% Answer Correctly

\(PE = mgh\)

\(PE = { 1 \over 2} mv^2\)

\(PE = { 1 \over 2} mg^2\)

\(PE = mg^2h\)


Solution

Gravitational potential energy is energy by virtue of gravity. The higher an object is raised above a surface the greater the distance it must fall to reach that surface and the more velocity it will build as it falls. For gravitational potential energy, PE = mgh where m is mass (kilograms), h is height (meters), and g is acceleration due to gravity which is a constant (9.8 m/s2).


4 If the radius of the axle is 7 and the radius of the wheel is 10, what is the mechanical advantage of this wheel and axle configuration?
41% Answer Correctly
3
0.7
7
10

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 7 and the output radius (where the resistance is being applied) is 10 for a mechanical advantage of \( \frac{7}{10} \) = 0.7


5

Friction between two or more solid objects that are not moving relative to each other is called:

73% Answer Correctly

static friction

kinetic friction

gravitational friction

dynamic friction


Solution

Static friction is friction between two or more solid objects that are not moving relative to each other. An example is the friction that prevents a box on a sloped surface from sliding farther down the surface.