Energy—How Things Work - Renewable and Non-renewable Energy

Energy is defined as the ability or capacity to do work. The standard unit of energy is the Joule ($J$).

Renewable Energy: These are sources that are replenished naturally and do not run out. Examples include Solar energy from the $Sun$, Wind energy, and Hydro-energy from $Water$.

Non-renewable Energy: These sources exist in limited quantities and take millions of years to form. Examples include fossil fuels like $Coal$, $Petroleum$, and $Natural Gas$.

Law of Conservation of Energy: Energy can neither be created nor destroyed; it can only be transformed from one form to another. For example, in a bulb, Electrical Energy $\rightarrow$ Light Energy + Heat Energy.

Mechanical Energy is the sum of Kinetic Energy ($K.E.$), which is energy due to motion, and Potential Energy ($P.E.$), which is energy due to position or rest.