Question

What is energy? What is the unit of energy?

Answer 1

The universe is made up of various forms of matter, and all forms of matter contain energy. The Sun – the ultimate energy source — is the source of all energy on Earth. Plants absorb light energy from the Sun and convert it into chemical energy through the process of photosynthesis. Plants' stored energy can be used in a variety of ways. Eating plant products as food, for example, provides energy for our bodies to function, whereas burning wood or coal (fossilized plants) generates heat and power.

Complete step by step solution:
Energy: The ability to do work is defined as energy. Work is done when a force given to an object causes it to move in the opposite direction of an opposing force. Work is done when, for example, a table is moved across a room against the resistance of the floor.
Unit of energy: Because energy is defined as work, the SI unit of energy is the joule $\left( J \right)$, named after James Prescott Joule and his investigations on the mechanical equivalent of heat. In slightly more basic words, $1$ joule equals $1$ newton meter and, in terms of SI base units,
$1J = 1kg{\left( {\dfrac{m}{s}} \right)^2} = 1\dfrac{{kg.{m^2}}}{{{s^2}}}$
CGS Unit of Energy:
The Erg equals ${10^{ - 7}}J$ . An erg is defined as the amount of work done by one dyne across a one-centimeter distance.
Additional information:
Forms of Energy:
Heat, kinetic or mechanical energy, light, potential energy, and electrical energy are all types of energy.
Heat, often known as thermal energy, is energy derived from the movement of atoms or molecules. It can be thought of as temperature-related energy.
Kinetic Energy - Kinetic energy is defined as the energy of motion. Kinetic energy is present in a swinging pendulum.
Potential energy is energy that exists as a result of an object's location. A ball sitting on a table, for example, has potential energy about the floor because gravity works on it.
Mechanical Energy - The sum of a body's kinetic and potential energy is referred to as mechanical energy.
Light - Photons are a type of energy.
Electrical energy is the energy generated by the movement of charged particles such as protons, electrons, or ions.
Magnetic Energy - This type of energy is produced by a magnetic field.
Chemical Energy - Chemical reactions produce or absorb chemical energy. It is created by atoms and molecules breaking or creating chemical bonds.
Nuclear energy is energy derived from interactions with an atom's protons and neutrons. Typically, this refers to a powerful force. Fission and fusion are two examples of energy release.

Note:
Potential energy and kinetic energy are the two fundamental types of energy. Potential energy is the energy associated with an object's relative position, composition, or state. Kinetic energy is the energy associated with the motion of an object. Water confined behind a dam, for example, has potential energy due to its elevation above ground. It gains kinetic energy as it runs downward via generators, which can be used to generate electricity in a hydroelectric power plant.