Force can be defined as the physical cause that tends to change the resting position or uniform motion or to change the shape and size of the body. Classification of Forces Forces are classified as contact and non – contact forces . Forces can be applied on a body by making physical contact or otherwise. Forces which act on a body through physical contact are contact forces. Forces which act on a body without making any physical contact with the body are known as non – contact forces . Based on their nature, forces can also be classified as: Mechanical force Magnetic force Gravitational force Electric force Nuclear force Mechanical force To hit a nail into a wall, we use a hammer. The force exerted by the hammer on the nail rives into the wall. Thus, in this case, the force makes a physical contact and displaces the mail Such a force is called contact force or in this case, it can also be called mechanic...