ASVAB Mechanical Comprehension Practice Test 418252 Results

Your Results Global Average
Questions 5 5
Correct 0 3.16
Score 0% 63%

Review

1

Which class of lever is used to increase force on an object in the same direction as the force is applied?

53% Answer Correctly

all of these

first

second

third
Solution

A second-class lever is used to increase force on an object in the same direction as the force is applied. This lever requires a smaller force to lift a larger load but the force must be applied over a greater distance. The fulcrum is placed at one end of the lever and mechanical advantage increases as the object being lifted is moved closer to the fulcrum or the length of the lever is increased. An example of a second-class lever is a wheelbarrow.

2 If the handles of a wheelbarrow are 2.5 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 0.5 ft. from the axle?
52% Answer Correctly
-39
34
850
42.2
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:
\( F_e = \frac{F_r d_r}{d_e} \)
\( F_e = \frac{170 \times 0.5}{2.5} \)
\( F_e = \frac{85.0}{2.5} \)
\( F_e = 34 \)
3

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

60% Answer Correctly

static uniformly distributed load

concentrated load

impact load

non-uniformly distributed 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.

4

Coplanar forces:

62% Answer Correctly

act along the same line of action

have opposite dimensions

pass through a common point

act in a common plane
Solution

Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.

5

On Earth, acceleration due to gravity (g) is approximately __________. 

81% Answer Correctly

1 m/s2

1 m/s

9.8 m/s2

6.67 x 10-11 m/s2
Solution

Newton's Law of Univeral Gravitation defines the general formula for the attraction of gravity between two objects:  \(\vec{F_{g}} = { Gm_{1}m_{2} \over r^2}\) . In the specific case of an object falling toward Earth, the acceleration due to gravity (g) is approximately 9.8 m/s2.