# Energy

Written by Jerry Ratzlaff on . Posted in Classical Mechanics

Energy, abbreviated as E, is never created or destroyed First Law of Thermodynamics, but it can be transferred from one object to another.  It also comes in many different forms (kinetic, potential, thermal, chemical, electrodynamic and nuclear) and can be converted from any one of these forms into any other, and vice versa.  Energy can be converted from one form to another in three basic ways: through the action of forces (gravitational forces, electric and magnetic force fields, frictional forces), when atoms absorb or emit photons of light and when nuclear reaction occurs.

## Energy Types

• Kinetic Energy  -  Energy of moving objects.
• Electrical Energy  -  Energy stored in an electric field or transported by an electric current.
• Mechanical Energy  -  The sum of the change in kinetic energy and potential energy generating from the force of gravity, external forces or the movement released in machine movement.
• Radiant Energy (electromagnetic)  -  Energy transmitted without the movement of mass.
• Sound Energy  -  Energy that we can hear.  It is a type of kinetic energy that moves through the air and other matter in the form of sound waves.
• Thermal Energy  -  The exertion of power that is created by heat, or the increase in temperature.
• Wind Energy  -  The kinetic energy of air in motion.
• Porential Energy  -  Energy that is stored.
• Chemical Energy  -  When two substances are combined or mixed together to produce a chemical reaction.
• Elastic Energy  -  The energy stored in objects as the result of deformation, such as a spring when stretching or compressing.
• Electrical Energy  -  Energy stored in an electric field or transported by an electric current.
• Gravitational Energy  -  The energy stored in an object due to its height above the earth.
• Magnetic Energy  -  A natural phenomenon by which some objects produce attractive or repulsive forces on other materials.
• Nuclear Energy  -  Energy stored in the nucleus of an atom.

## Energy formula

$$\large{ E = m \; U }$$

$$\large{ E = F \; l = \frac{m \; l^2}{t^2} }$$

Symbol English Metric
$$\large{ E }$$ = energy $$\large{lbf-ft}$$ $$\large{J}$$
$$\large{ F }$$ = force $$\large{lbf}$$ $$\large{N}$$
$$\large{ U }$$ = internal energy $$\large{Btu}$$ $$\large{\frac{kg-m^2}{s^2}}$$
$$\large{ l }$$ = length $$\large{ft}$$ $$\large{m}$$
$$\large{ m }$$ = mass $$\large{lbm}$$ $$\large{kg}$$
$$\large{ t }$$ = time $$\large{sec}$$ $$\large{s}$$