Free ASVAB Practice Tests | ASVAB Test Bank

Word Knowledge

The soldiers cherished the kindly Nurse Nightingale for her pathos.

compassion

Sympathetic pity.

Automotive Information

Which of the following is not an advantage that disc brakes have over drum brakes?

use less brake fluid

Brakes utlize friction to slow vehicle tires. Drum brakes employ a cast iron drum that roates with the vehicle axle. When hydraulic pressure is applied to the brake assemblies at the wheels, internal pistons expand and push brake shoes outward into contact with the brake drum slowing the rotation of the axle. More powerful disc brakes operate by pinching a rotating disc betweeen two brake pads and allow for a larger surface area to contact the disc, provide more force, and are more easily cooled.

General Science

In the metric system, what prefix represents 10³?

kilo

Kilo is the metric system prefix for 10³.

Word Knowledge

Civility most nearly means:

courtesy

Politeness.

General Science

The pitch of the siren of an approaching ambulance changes as it approaches you. This is an example of which of the following?

Doppler effect

The Doppler effect occurs when the source or listener (or both) of sound waves is moving. If they're moving closer together, the listener perceives the sound with a higher pitch and, when they're moving apart, the listener perceives the sound with a lower pitch.

Electronics Information

This circuit component symbol represents a(n):

fuse

Fuses are thin wires that melt when the current in a circuit exceeds a preset amount. They help prevent short circuits from damaging circuit components when an unusually large current is applied to the circuit, either through component failure or spikes in applied voltage.

General Science

Which of these parts of digestion takes place in the mouth?

breaking down starches

Digestion begins in the mouth where the teeth and tongue break down food mechanically through chewing and saliva, via the enzyme salivary amylase, starts to break starches down chemically. From the mouth, food travels down the esophagus where contractions push the food into the stomach.

Automotive Information

Which of the following is the result of the air-fuel mixture exploding instead of burning?

detonation

Normal combustion in an engine is initiated by a spark plug and results in the complete burning of the air-fuel mixture. If combustion is initiated by a source other than the spark plug, by a hot spot in the cylinder or combustion chamber for example, pre-ignition results. Detonation results if the air-fuel mixture explodes instead of burning. Detonation can cause extremes in pressure in the combustion chamber leading to engine damage.

General Science

Acceleration is the rate of change of velocity per unit of time. Which of these is the formula for acceleration?

\(\vec{a} = { \Delta \vec{v} \over t }\)

Acceleration is the rate of change of velocity per unit of time. In physics, the delta symbol (\(\Delta\)) represents change so the formula for acceleration becomes \(\vec{a} = { \Delta \vec{v} \over t }\)

Mechanical Comprehension

If a 25 lbs. weight is placed 3 ft. from the fulcrum at the blue arrow and the green box is 6 ft. from the fulcrum, how much would the green box have to weigh to balance the lever?

12.5 lbs.

To balance this lever the torques on each side of the fulcrum must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:

R_ad_a = R_bd_b

where a represents the left side of the fulcrum and b the right, R is resistance (weight) and d is the distance from the fulcrum.

Solving for R_a, our missing value, and plugging in our variables yields:

R_a = \( \frac{R_bd_b}{d_a} \) = \( \frac{25 lbs. \times 3 ft.}{6 ft.} \) = \( \frac{75 ft⋅lb}{6 ft.} \) = 12.5 lbs.