Free ASVAB Practice Tests | ASVAB Test Bank

Word Knowledge

Felicia's servile attitude annoyed her boss, who preferred an assistant with more backbone.

slavish

Fearfully submissive.

Electronics Information

Direct current flows from the __________ terminal of the voltage source to the __________ terminal.

negative, positive

Direct current flows in only one direction in a circuit, from the negative terminal of the voltage source to the positive. A common source of direct current (DC) is a battery.

Mechanical Comprehension

If the green box weighs 25 lbs. and 75 lbs. of force is applied 5 ft. from the fulcrum at the blue arrow, how far from the fulcrum would the green box need to be placed to balance the lever?

15 ft.

To balance this lever the torques at the green box and the blue arrow 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 green box and b the blue arrow, R is resistance (weight/force) and d is the distance from the fulcrum.

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

d_a = \( \frac{R_bd_b}{R_a} \) = \( \frac{75 lbs. \times 5 ft.}{25 lbs.} \) = \( \frac{375 ft⋅lb}{25 lbs.} \) = 15 ft.

Word Knowledge

The arrogant writer did not hide his disdain for his uneducated dinner companion.

scorn

Feeling of contempt.

Automotive Information

The spark plug fires during which engine stoke?

power

During the power stroke, just before the piston reaches top dead center, the spark plug fires and ignites the compressed air-fuel mixture. The resulting expansion due to combustion pushes the piston back down the cylinder toward bottom dead center.

Mechanical Comprehension

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

weight

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.

Automotive Information

What does the timing belt do?

synchronizes the camshaft and the crankshaft

Maintaining proper synchronization between the rotation of the camshaft and the rotation of the crankshaft is critical to ensure that the engine's valves open and close at the proper times during each cylinder's intake and exhaust strokes.

Mechanical Comprehension

A wedge converts force applied to its blunt end into force __________ its inclined surface.

perpendicular to

The wedge is a moving inclined plane that is used to lift, hold, or break apart an object. A wedge converts force applied to its blunt end into force perpendicular to its inclined surface. In contrast to a stationary plane where force is applied to the object being moved, with a wedge the object is stationary and the force is being applied to the plane. Examples of a wedge include knives and chisels.

Electronics Information

In an electrical circuit, resistors have fixed or __________ resistance.

variable

Resistors are used to limit voltage and/or current in a circuit and can have a fixed or variable resistance. Variable resistors (often called potentiometers or rheostats) are used when dynamic control over the voltage/current in a circuit is needed, for example, in a light dimmer or volume control.

Shop Information

Which of the following is not an advantage of using a ratchet with a larger point-sized socket?

larger point sizes allow easier alignment

A ratchet (or socket wrench) is a wrench that applies torque in only one direction with a handle that can be moved back and forth without losing contact with the fastener. A ratchet uses variable attachments called sockets which come in a variety of drive sizes based on the size of the opening that attaches to the ratchet. Sockets with the same drive size will vary in the shape (six-point, twelve-point) and size of the nut opening that attaches to the fastener being tightened or loosened. Smaller point sized sockets are stronger and can apply greater torque while larger point sizes allow easier alignment.