1) Work is done only when a body undergoes displacement in the direction of the applied force. 2) If a force F Newtons is applied continuously on a body and the body undergoes a displacement of S meters in the direction of the force, then the work done by the applied force is W=F*S. 3) Work is measured in Joules (J) which is the unit of force (Newtons) multiplied by the unit of displacement (meters).