ASVAB Mechanical Comprehension Practice Test 748669 Results

Your Results Global Average
Questions 5 5
Correct 0 2.94
Score 0% 59%

Review

1

A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?

50% Answer Correctly

tension is equal in all parts of the rope

in the middle

near the truck

near the car
Solution

Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress.

2

Which of the following represents how much two materials resist sliding across each other?

53% Answer Correctly

coefficient of friction

normal friction

static friction

kinetic friction
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.

3

The mechanical advantage of a wheel and axle is equal to the:

61% Answer Correctly

difference in the diameters of the wheels

difference in the lengths of the axles

ratio of the diameters of the wheels

length of the axle
Solution

A wheel and axle uses two different diameter wheels mounted to a connecting axle. Force is applied to the larger wheel and large movements of this wheel result in small movements in the smaller wheel. Because a larger movement distance is being translated to a smaller distance, force is increased with a mechanical advantage equal to the ratio of the diameters of the wheels. An example of a wheel and axle is the steering wheel of a car.

4

An object's resistance to changes in direction is known as:

81% Answer Correctly

mass

kinetic energy

weight

inertia
Solution

The more mass a substance has the more force is required to move it or to change its direction. This resistance to changes in direction is known as inertia.

5 What is the power output of a 9 hp engine that's 40% efficient?
40% Answer Correctly
5940 \( \frac{ft⋅lb}{s} \)
1980 \( \frac{ft⋅lb}{s} \)
0 \( \frac{ft⋅lb}{s} \)
360 \( \frac{ft⋅lb}{s} \)
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 9 hp x 550 \( \frac{ft⋅lb}{s} \) = 4950 \( \frac{ft⋅lb}{s} \)
\( P_{o} = \frac{E \times P_{i}}{100} = \frac{40 \times 4950 \frac{ft⋅lb}{s}}{100} \) \( = \frac{198000 \frac{ft⋅lb}{s}}{100} \) = 1980 \( \frac{ft⋅lb}{s} \)