Final answer:
Energy is defined as the ability to do work and can exist in various forms such as mechanical, electrical, light, and heat energy. All forms of energy can perform work, and energy is conserved, meaning it can neither be created nor destroyed.
Step-by-step explanation:
Energy is best defined as the ability to do work. This includes causing movement or changing matter in some way. Knowing that energy is the capacity to do work, we can see that it is closely related to work itself. Energy can take a variety of forms, including mechanical energy (kinetic and potential), electrical energy, light energy, and heat energy. All of these forms of energy can be used to perform work. Furthermore, the first law of thermodynamics states that energy cannot be created or destroyed, but it can be transferred or transformed from one form to another. Therefore, energy in the form of heat, work, and internal energy are all capable of doing work, assuming they can be harnessed effectively.