ASVAB Mechanical Comprehension Practice Test 271725 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.41
Score	0%	68%

Review

1 What is the power output of a 9 hp engine that's 75% efficient?

40% Answer Correctly

	7425 \( \frac{ft⋅lb}{s} \)
	928.1 \( \frac{ft⋅lb}{s} \)
	3712.5 \( \frac{ft⋅lb}{s} \)
	8 \( \frac{ft⋅lb}{s} \)

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 \( \frac{ft⋅lb}{s} \), P_i becomes 9 hp x 550 \( \frac{ft⋅lb}{s} \) = 4950 \( \frac{ft⋅lb}{s} \)
\( P_{o} = \frac{E \times P_{i}}{100} = \frac{75 \times 4950 \frac{ft⋅lb}{s}}{100} \) \( = \frac{371250 \frac{ft⋅lb}{s}}{100} \) = 3712.5 \( \frac{ft⋅lb}{s} \)

Tension is a force that does which of the following?

75% Answer Correctly

	stretches an object
	slows an object
	compacts an object
	heats up an object

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.

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

81% Answer Correctly

	mass
	inertia
	weight
	kinetic energy

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.

Potential energy is energy that has the potential to be converted into what?

80% Answer Correctly

	kinetic energy
	heat
	work
	power

Solution

Potential energy is the energy of an object by virtue of its position relative to other objects. It is energy that has the potential to be converted into kinetic energy.

Gear ratio indicates which of the following about two connected gears?

59% Answer Correctly

	mechanical advantage
	efficiency
	power conversion
	work done

Solution

The mechanical advantage (amount of change in speed or torque) of connected gears is proportional to the number of teeth each gear has. Called gear ratio, it's the ratio of the number of teeth on the larger gear to the number of teeth on the smaller gear. For example, a gear with 12 teeth connected to a gear with 9 teeth would have a gear ratio of 4:3.