ASVAB Mechanical Comprehension Practice Test 363689 Results

Your Results Global Average
Questions 5 5
Correct 0 2.93
Score 0% 59%

Review

1

What type of load varies with time or affects a structure that experiences a high degree of movement?

66% Answer Correctly

impact load

concentrated load

static 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.

2 What is the power output of a 6 hp engine that's 70% efficient?
39% Answer Correctly
2310 \( \frac{ft⋅lb}{s} \)
0 \( \frac{ft⋅lb}{s} \)
1155 \( \frac{ft⋅lb}{s} \)
577.5 \( \frac{ft⋅lb}{s} \)
Solution
\( Efficiency = \frac{Power_{out}}{Power_{in}} \times 100 \)
Solving for power out: \( P_{o} = \frac{E \times P_{i}}{100} \)
Knowing that 1 hp = 550 \( \frac{ft⋅lb}{s} \), Pi becomes 6 hp x 550 \( \frac{ft⋅lb}{s} \) = 3300 \( \frac{ft⋅lb}{s} \)
\( P_{o} = \frac{E \times P_{i}}{100} = \frac{70 \times 3300 \frac{ft⋅lb}{s}}{100} \) \( = \frac{231000 \frac{ft⋅lb}{s}}{100} \) = 2310 \( \frac{ft⋅lb}{s} \)
3

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

second

third

first
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.

4

Which of the following will increase the mechanical advantage of a second-class lever?

55% Answer Correctly

decrease the length of the lever

move the fulcrum between the force and the object being lifted

move the object being lifted closer to the fulcrum

move the object being lifted farther away from the fulcrum
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.

5

Which of the following surfaces would have the highest coefficient of friction?

77% Answer Correctly

ice

steel

concrete

marble
Solution

Coefficient of friction (μ) represents how much two materials resist sliding across each other.  Smooth surfaces like ice have low coefficients of friction while rough surfaces like concrete have high μ.