ASVAB Mechanical Comprehension Practice Test 890122 Results

Your Results Global Average
Questions 5 5
Correct 0 3.34
Score 0% 67%

Review

1 If the handles of a wheelbarrow are 1.0 ft. from the wheel axle, how many pounds of force must you exert to lift the handles if it's carrying a 260 lbs. load concentrated at a point 0.5 ft. from the axle?
52% Answer Correctly
0
260
130
61.7
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:
\( F_e = \frac{F_r d_r}{d_e} \)
\( F_e = \frac{260 \times 0.5}{1.0} \)
\( F_e = \frac{130.0}{1.0} \)
\( F_e = 130 \)
2

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

81% Answer Correctly

1 m/s

9.8 m/s2

1 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. 

3

What type of load acts on a relatively small area of a structure?

74% Answer Correctly

non-uniformly distributed load

concentrated load

impact load

dynamic 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

Normal force is generally equal to the __________ of an object.

61% Answer Correctly

weight

mass

density

coefficient of friction
Solution

Normal force arises on a flat horizontal surface in response to an object's weight pressing it down. Consequently, normal force is generally equal to the object's weight.

5

A box is resting on a smooth floor. Static friction is present:

59% Answer Correctly

if the coefficient of friction is greater than one

at all times

when an attempt is made to move the box

only if normal force is present
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).