Free ASVAB Practice Tests | ASVAB Test Bank

Mechanical Comprehension

The measure of how much of the power put into a machine is turned into movement or force is called:

efficiency

The efficiency of a machine describes how much of the power put into the machine is turned into movement or force. A 100% efficient machine would turn all of the input power into output movement or force. However, no machine is 100% efficient due to friction, heat, wear and other imperfections that consume input power without delivering any output.

Math Knowledge

A(n) __________ is to a parallelogram as a square is to a rectangle.

rhombus

A rhombus is a parallelogram with four equal-length sides. A square is a rectangle with four equal-length sides.

Mechanical Comprehension

If you lift a 30 lbs. rock 24 ft. from the ground, how much work have you done?

720 ft⋅lb

Work is force times distance. In this case, the force is the weight of the rock so:
\( W = F \times d \)
\( W = 30 \times 24 \)
\( W = 720 \)

Electronics Information

This circuit component symbol represents a(n):

inductor

An inductor is coiled wire that stores electric energy in the form of magnetic energy and resists changes in the electric current flowing through it. If current is increasing, the inductor produces a voltage that slows the increase and, if current is decreasing, the magnetic energy in the coil opposes the decrease to keep the current flowing longer. In contrast to capacitors, inductors allow DC to pass easily but resist the flow of AC.

General Science

An element in the physical state of __________ maintains a constant volume but their shape depends upon the shape of their container.

liquid

In the liquid state, molecules flow freely around each other and exist at a higher temperature range than the same substance in a solid state. Liquids maintain a constant volume but their shape depends upon the shape of their container.

Mechanical Comprehension

The mechanical advantage of connected gears is proportional to which characteristic of the gears?

number of teeth

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.

Automotive Information

Engine oil viscosity is rated using the format XW-XX with the number preceding the W indicating viscosity at __________ ℉ and the XX indicating viscosity at __________ ℃.

0, 100

The primary component of the lubrication system is engine oil. Engines require oil blends with different thickness (viscosity) and additives depending on their operating conditions. Viscosity is rated using the format XW-XX with the number preceding the W (winter) rating the oil’s viscosity at 0 ℉ (-17.8 ℃) and the XX indicating viscosity at 100 ℃.

General Science

Materials like metals that transfer heat efficiently are called:

conductors

Heat is always transferred from warmer to cooler environments and conduction is the simplest way this transfer can occur. It is accomplished through direct contact between materials and materials like metals that transfer heat efficiently are called conductors while those that conduct heat poorly, such as plastic, are called insulators.

Shop Information

When cutting hard metals with a hacksaw you should choose a blade with __________ teeth per inch (TPI).

high

Blades with more and smaller teeth (high TPI) cut harder metals more effectively while blades with fewer and larger teeth (low TPI) cut softer metals more effectively.

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.