Free ASVAB Practice Tests | ASVAB Test Bank

Word Knowledge

Thelma tended to polarize discussions rather than to encourage compromise.

divide

To break up into opposing groups.

Shop Information

Which of the following determines whether a socket can be used with a particular ratchet?

the drive size

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.

Math Knowledge

If angle a = 53° and angle b = 27° what is the length of angle d?

127°

An exterior angle of a triangle is equal to the sum of the two interior angles that are opposite:

d° = b° + c°

To find angle c, remember that the sum of the interior angles of a triangle is 180°:

180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 53° - 27° = 100°

So, d° = 27° + 100° = 127°

A shortcut to get this answer is to remember that angles around a line add up to 180°:

a° + d° = 180°
d° = 180° - a°
d° = 180° - 53° = 127°

Mechanical Comprehension

If you have a gear train with three gears, the first with 24 teeth, the second with 16 teeth, and the third with 4 teeth, what is its mechanical advantage?

The mechanical advantage of a gear train is its gear ratio. The gear ratio (V_r) is the product of the gear ratios between the pairs of meshed gears. Let N represent the number of teeth for each gear:

V_r = \( \frac{N_1}{N_2} \) \( \frac{N_2}{N_3} \) \( \frac{N_3}{N_4} \) ... \( \frac{N_n}{N_{n+1}} \)

In this problem, we have three gears so the equation becomes:

V_r = \( \frac{N_1}{N_2} \) \( \frac{N_2}{N_3} \) = \( \frac{24}{16} \) \( \frac{16}{4} \) = \( \frac{24}{4} \) = 6

Electronics Information

Why does current in an electric circuit create heat?

heat is created when the current overcomes resistance in the wire

Current in an electric circuit creates heat when the current overcomes resistance in the wire.

Word Knowledge

Liability most nearly means:

handicap

A person or thing whose presence or behavior is likely to cause embarrassment or put one at a disadvantage.

Mechanical Comprehension

Force of friction due to kinetic friction is __________ the force of friction due to static friction.

the same as

The formula for force of friction (F_f) is the same whether kinetic or static friction applies: F_{f =}μF_N. To distinguish between kinetic and static friction, μ_k and μ_s are often used in place of μ.

Mechanical Comprehension

What is the efficiency of a machine has work input of 100 ft⋅lb and work output of 35 ft⋅lb?

35%

Due to friction, a machine will never be able to utilize 100% of its work input. A certain percentage of that input will be lost in overcoming friction within the machine. Effeciency is a measure of how much of a machine's work input can be turned into useful work output and is calculated by dividing work output by work input and multiplying the result by 100:
\( Efficiency = \frac{Work_{out}}{Work_{in}} \times 100 \) \( = \frac{35 ft⋅lb}{100 ft⋅lb} \times 100 \) \( = 35% \) %

Word Knowledge

Clarence, an irrepressible comic, was held after cass for his buffoonery.

jocularity

Foolish behavior.

Automotive Information

Which of the following enables heat transfer from the cylinder heads to the coolant?

water jacket

A water jacket is a coolant-filled casing that allows heat transfer from the engine block and cylinder heads to the liquid coolant.