3. Work Work is done when a force produces motion for exp. When a engine moves a train along a railway line, it said to be doing work; a horse pulliong the cart is also doin work; and a man climbing the stairs of house is also doing work in moving himself against the force of gravity. Work = Force X Distance W = F X S

4. Unit of work  The unit of work is newton metre which is written as Nm. This unit of work is called joule. When a force of 1 newton moves a body through a distance of 1 newton moves a body through a distance of 1 metre in its own direction, then the work is known as 1 joule. The SI unit of work is joule work is a scalar quantity.  1Joule = 1Newton X 1Metre  1J = 1Nm

5. Energy Energy is the ability to do work. The amount of Energy possessed by a body is equal to the amount of work it can do when its energy is released.

6. Unit of Energy  The unit of Work 7 energy are the same. The SI unit of energy is joule. Which is denoted by J. The energy reguired to do 1 joule of work is called 1 joule energy. Joule is a small unit of energy a bigger unit of energy called ‘kilojoule’. The symbol of kilojoule is KJ. 1Kilojoule = 1000joule 1KJ = 1000J The Unit of energy called ‘joule’ is named after a British Physicist James Pescott Joule.

7. The main Forms of Energy 1.Kinetic Energy 2.Potential Energy 3.Chemical Energy 4.Heat Energy 5.Fight Energy 6.Sound Energy 7.Electrical Energy 8.Nuclear Energy

8. Kinetic Energy The energy of a body due to its motion is called Kinetic energy. Formula of Kinetic Energy Kinetic Energy = ½ mv2 Where, m= mass of the body V= velocity of the body

9. Potential Energy The Energy of the body due to its position or change in shape is known as potential energy. Formula of potential energy Potential Energy =m x g x h m=mass of the body g = acceleration due to gravity h= height of body