Force may be defined as any action that tends to change the state of rest of a body to which it is applied. A force can be defined quantitatively as the product of the mass of the body that the force is acting on and the acceleration of the force. P = m a where, P = applied force m = mass of the body (kg) a = acceleration caused by the force (m/Square Sec) The force is an important factor in the field of Mechanics, which may be broadly defined as an agent which produces or tends to produce, destroys or tends to destroy motion. Force is a vector quantity. Specifications or characteristics of a force are: - Magnitude of the force (i.e. 100 N, 50 KN) - Direction of the line, along which the force acts (i.e. along OX, OY, @ 30 ° NE). It is known as line of action of force. - Nature of the force. (i.e. pull or push). - The point @ which the force acts on the body. Effects of a Force - It m