Power
Power (physics), in physics and engineering, the rate of performing work or transferring energy . Work is equal to the force applied to move an object multiplied by the distance the object travels. Power measures how quickly the work is done. For example, suppose a person wants to push a heavy box across a room. To overcome the friction between the bottom of the box and the floor, the person must apply force to the box to keep it moving. Since friction is independent of an object's velocity along a sliding surface, no matter how quickly the person pushes the box across the floor, the force applied is the same. Now suppose the person pushes the box from one end of the room to the other in ten seconds, then pushes the box back to its original position in five seconds. In each trip across the room, the force applied and the distance the box is moved is the same, so the work done in each case is the same. But the second time the box is pushed across the room, the person has to apply m