Nothing can move or work without energy. We need energy for our survival. The amount of work we do everyday depends on our energy level. We get energy from the food we take. Plants need energy for growth. Engine also needs energy for its functioning. Some engines use electricity and sonic need fuel for energy. Energy is stored in fuel.
What do we mean by energy? The energy of a body means its ability to work. So the body which is able to work has energy in it and the body that does not have energy in it cannot work.
When we say a body has energy in it we mean the body can apply force on other and can work. Again the amount of work done on a body is equal to the energy we use.
The energy of a body refers to its ability to work. Here work means the transformation of energy from one form to another. It means that the total amount of work that a body can do is its energy. The amount of work a body can do is the measure of its energy. So, the amount of work done is the amount of energy used.
Therefore, Work done = Energy used
Energy has no direction. So it is a scalar quantity.
The unit of energy and work is the same and it is joule (J)