What is Energy?

Energy is the capacity of a body to perform transformations and do work. It can't be destroyed or created, it only can be transformed. Humans take their energy from food, and after we transform this energy into metabolic and muscular energy. Modern devices need electrical energy, for example; cars have motors that use gasoline or diésel as a source of energy.

         

➡ FORMS OF ENERGY.

In nature, these forms of energy can manifest in different ways:

POTENTIAL: Associated with the height of an object above the ground, or the storage of energy in a spring.
KINETIC: The energy of physical movement.
MECHANICAL: The sum of potential and kinetic energy.
SOUND: The energy of sound waves , which are prodced by vibrations and propagated hrough a physical médium.
ELECTRICAL: The product of an electrical current.
NUCLEAR: tThe energy in the nucleus of an atom.
LUMINOUS: Associated with light.
THERMAL OR CALORIFIC: Associated with the movment of particles in matter.
CHEMICAL: Results from the formation or descomposition of substances. For example, metabolic energy is generated by living organisms that perform chemical transformations during digestión and respiration.
ELECTROMAGNETIC: Occurs when electrical currents créate magnetic fields.

➡ UNITS OF MEASUREMENT FOR ENERGY.

Energy is measured in joules (J) , and when it takes the form of heat, we express it as calories. Relationship: 1 cal= 4.18 J.

➡ POWER.

Power is the amount of work that it can do a machine in a certain amount of time. Relationship: P=W/t. (W: work expressed in joules and t: time expressed in seconds)
In machines, the output is always less tan their energy input. This happens because some energy is always lost to friction, vibration and heat. Relationship:

                      Energy conversión efficiency (%)= output/input * 100