ASVAB Mechanical Comprehension Practice Test 3084 Results

Your Results Global Average
Questions 5 5
Correct 0 2.73
Score 0% 55%

Review

1

Which of the following statements about drag is false?

58% Answer Correctly

drag occurs during movement through a fluid

the amount of drag depends on the speed of an object

slower objects experience more drag than faster objects

the amount of drag depends on the shape of an object
Solution

Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area.

2

The science that deals with motion and the forces that produce motion is called which of the following?

57% Answer Correctly

aeronautics

mechanics

physics

engineering
Solution

Mechanics deals with motion and the forces that produce motion.

3

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

They have done an equal amount of work

Sam

Neither have done any work

Lisa
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.

4

For any given surface, the coefficient of static friction is ___________ the coefficient of kinetic friction.

54% Answer Correctly

lower than

higher than

opposite

equal to
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).

5 If the handles of a wheelbarrow are 1.5 ft. from the wheel axle, how many pounds of force must you exert to lift the handles if it's carrying a 170 lbs. load concentrated at a point 1.0 ft. from the axle?
52% Answer Correctly
119.9
170
0
113.3
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:
\( F_e = \frac{F_r d_r}{d_e} \)
\( F_e = \frac{170 \times 1.0}{1.5} \)
\( F_e = \frac{170.0}{1.5} \)
\( F_e = 113.3 \)