Energy Definition. Energy is defined as the capacity of a physical system to perform work. However, it's important to keep in mind that just because energy exists, it doesn't means it's necessarily available to do work.
https://www.thoughtco.com/energy-definition-and-examples-2698976
(ĕn′ər-jē) 1. The capacity or power to do work, such as the capacity to move an object (of a given mass) in a given direction by the application of force. Energy can exist in a variety of forms, such as electrical, mechanical, chemical, thermal, or nuclear, and can be transformed from one form to another.
http://www.thefreedictionary.com/energy
If you do 100 joules of work in one second (using 100 joules of energy), the power is 100 watts. Work-Energy Principle. The change in the kinetic energy of an object is equal to the net work done on the object. Average impact force x distance traveled = change in kinetic energy. Car crash example.
http://hyperphysics.phy-astr.gsu.edu/hbase/work.html
Forms of Energy. Energy exists in several forms such as heat, kinetic or mechanical energy, light, potential energy, and electrical energy. Heat - Heat or thermal energy is ​energy from the movement of atoms or molecules. It may be considered as energy relating to temperature.
https://www.thoughtco.com/energy-definition-and-examples-2698976
In quantum mechanics, energy is defined in terms of the energy operator as a time derivative of the wave function. The Schrödinger equation equates the energy operator to the full energy of a particle or a system. Its results can be considered as a definition of measurement of energy in quantum mechanics.
https://en.wikipedia.org/wiki/Energy
refers to an activity involving a force and movement in the directon of the force. A force of 20 newtons pushing an object 5 meters in the direction of the force does 100 joules of work. Energy. is the capacity for doing work. You must have energy to accomplish work - it is like the currency for performing work. To do 100 joules of work, you must expend 100 joules of energy.
http://hyperphysics.phy-astr.gsu.edu/hbase/work.html
The capacity of a body to do work. Energy occurs in several forms-potential as in a compressed spring or a mass in a high position, kinetic as in motion, chemical as in petroleum and nuclear as in the binding forces of the atomic nucleus. Its effect, when manifested, is to bring about a change of some kind.
http://medical-dictionary.thefreedictionary.com/Energy+(chemistry)
Energy exists in several forms such as heat, kinetic or mechanical energy, light, potential energy, and electrical energy. 1  Heat - Heat or thermal energy is ​energy from the movement of atoms or molecules. 2  Kinetic Energy - Kinetic energy is energy of motion. 3  Potential Energy - This is energy due to an objects position.
https://www.thoughtco.com/energy-definition-and-examples-2698976
The capacity to do work, measured in joules Types Potential/stored energy, kinetic/in motion energy. See Activation energy, Adaptation energy, Binding energy, Biomass energy, Bond dissociation energy, Department of Energy, Orgone energy.
http://medical-dictionary.thefreedictionary.com/Energy+(chemistry)
en·er·gy. 1. The capacity or power to do work, such as the capacity to move an object (of a given mass) in a given direction by the application of force. Energy can exist in a variety of forms, such as electrical, mechanical, chemical, thermal, or nuclear, and can be transformed from one form to another.
http://www.thefreedictionary.com/energy
energy is defined as the capacity to
Energy is defined as the capacity to of a physical system to perform work. An energy is defined as the capacity of a physical system to perform work.  