Free ASVAB Practice Tests | ASVAB Test Bank

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.

Mechanical Comprehension

Sam can do 50 ft. lb. of work in 2 minutes and 5 seconds. What would Sam have to do to increase his power output?

do the work in 2 minutes

Power is the rate of doing work or \(\frac{W}{t}\). To increase power, increase the work being done in the same amount of time or do the same amount of work in less time.

Math Knowledge

Solve for c:
9c - 9 < \( \frac{c}{5} \)

c < 1\(\frac{1}{44}\)

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the < sign and the answer on the other.

9c - 9 < \( \frac{c}{5} \)
5 x (9c - 9) < c
(5 x 9c) + (5 x -9) < c
45c - 45 < c
45c - 45 - c < 0
45c - c < 45
44c < 45
c < \( \frac{45}{44} \)
c < 1\(\frac{1}{44}\)

Word Knowledge

Clarity most nearly means:

lucidity

Clearness.

General Science

Which of the following is not true about simple magnets?

opposite poles repel each other

Simple magnets have two poles, north and south, and opposite poles attract each other (N attracts S, S attracts N). Likewise, the same pole of two magnets repel (N repels N, S repels S). The Earth has a magnetic field and North and South Poles which enables the use of a magnetic compass to determine direction.

General Science

Leafy vegetables, beans, potatoes, fruits, and whole grains are good sources of:

fiber

Fiber provides bulk to help the large intestine carry away waste. Good sources of fiber are leafy vegetables, beans, potatoes, fruits, and whole grains.

Mechanical Comprehension

When all forces acting on a system cancel each other out, this is called:

equilibrium

When a system is stable or balanced (equilibrium) all forces acting on the system cancel each other out. In the case of torque, equilibrium means that the sum of the anticlockwise moments about a center of rotation equal the sum of the clockwise moments.

Mechanical Comprehension

A box is resting on a smooth floor. Static friction is present:

when an attempt is made to move the box

For any given surface, the coefficient of static friction is higher than the coefficient of kinetic friction. More force is required to initally get an object moving than is required to keep it moving. Additionally, static friction only arises in response to an attempt to move an object (overcome the normal force between it and the surface).

Electronics Information

Use Ohm's Law to calculate the value of resistance in this circuit if voltage is 40 volts and current is 2 amps.

20 Ω

Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.

Solved for resistance, R = \( \frac{V}{I} \) = \( \frac{40}{2} \) = 20 Ω

Shop Information

You're creating a tube out of a sheet of metal. What type of fastener are you likely to use?

rivet

A nail is a short pin-shaped shaft of steel that's typically used to fasten pieces of wood together. It has a flat head on one end and a point on the other. A rivet consists of a cylindrical shaft with a head on one end and a tail on the other. When the rivet is installed, the tail is expanded and reshaped to form another head, creating a dumbell shape that will hold two surfaces together semi-permanently.