Free ASVAB Practice Tests

Current is the rate of flow of electrons per unit time and is measured in amperes (A). A coulomb (C) is the quantity of electricity conveyed in one second by a current of one ampere.

Rising into the atmosphere, the water condenses into clouds. When the clouds become too saturated with water, the water is released as snow or ice precipitation which may warm as it falls to reach Earth as rain.

A clamp applies pressure to prevent two objects from moving relative to each other, for example, to keep to pieces of wood together while the glue between the dries. A clamp is commonly made of metal and shaped like the letter C with a perpendicular flat-edged plate providing variable pressure between it and the top of the C as a screw to which it is attached is tightened and released.

Kinetic energy is the energy posessed by a moving object. Potential energy is stored energy in a stationary object based on its location, position, shape, or state.

Newton's law of universal gravitation defines gravity: All objects in the universe attract each other with an equal force that varies directly as a product of their masses, and inversely as a square of their distance from each other. Expressed as a formula:  \(\vec{F_{g}} = { Gm_{1}m_{2} \over r^2}\) where r is the distance between the two objects and G is the gravitational constant with a value of 6.67 x 10^-11.

Veins carry blood back to the heart from the body. While arteries are thick-walled because they carry oxygenated blood at high pressure, veins are comparatively thin-walled as they carry low-pressure deoxygenated blood. Like the heart, veins contain valves to prevent blood backflow.

Tertiary consumers eat primary consumers and secondary consumers and are typically carnivorous predators. Tertiary consumers may also be omnivores. Examples include wolves, sharks, and human beings.

Resistors can be chosen in a wide variety of values to control the voltage in a circuit, limit the current, or moderate the heat produced by the components in the circuit.

The rows of the Periodic Table are called periods and contain elements that have the same number of electron shells ordered from lower to higher atomic number. 

In contrast to the constant one-way flow of direct current, alternating current changes direction many times each second. Electricity is delivered from power stations to customers as AC because it provides a more efficient way to transport electricity over long distances.