ASVAB Mechanical Comprehension Practice Test 180753 Results

Your Results Global Average
Questions 5 5
Correct 0 3.46
Score 0% 69%

Review

1 What is the mechanical advantage of this inclined plane if the length of the ramp is 9 ft. and the height of the green box is 3 ft.?
82% Answer Correctly
4.5
3
3.3
2.7
Solution

The mechanical advantage (MA) of an inclined plane is the effort distance divided by the resistance distance. In this case, the effort distance is the length of the ramp and the resistance distance is the height of the green box:

MA = \( \frac{d_e}{d_r} \) = \( \frac{9 ft.}{3 ft.} \) = 3

2

The force required to initally get an object moving is __________ the force required to keep it moving. 

76% Answer Correctly

lower than

higher than

opposite

the same as
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).

3

For a hydraulic system, pressure applied to the input of the system will increase the pressure in which parts of the system?

58% Answer Correctly

the portions of the system at an altitude below the input

all of these are correct

the portions of the system at an altitude above the input

everywhere in the system
Solution

Pascal's law states that a pressure change occurring anywhere in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere. For a hydraulic system, this means that a pressure applied to the input of the system will increase the pressure everywhere in the system.

4

When all forces acting on a system cancel each other out, this is called:

80% Answer Correctly

equilibrium

stasis

rest

potential energy
Solution

When a system is stable or balanced (equilibrium) all forces acting on the system cancel each other out. In the case of torque, equilibrium means that the sum of the anticlockwise moments about a center of rotation equal the sum of the clockwise moments.

5 If the handles of a wheelbarrow are 1.5 ft. from the wheel axle and the load is concentrated at a point 0.5 ft. from the axle, how many pounds of load will a 170 lbs. force lift?
47% Answer Correctly
44.6
0
1730
510
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 resistance force:
\( F_r = \frac{F_e d_e}{d_r} \)
\( F_r = \frac{170 \times 1.5}{0.5} \)
\( F_r = \frac{255.0}{0.5} \)
\( F_r = 510 \)