Work, power, and the work-energy theorem

In physics, work is done when a force moves an object in the direction of the force: work = force x distance moved in that direction, measured in joules. No work is done if the object does not move, like pushing on a solid wall, or if the force is perpendicular to the motion, like the upward force you use to carry a box across a level room at constant speed. Lifting a 100 N box up 2 m takes 200 J of work. Power is how fast work is done, power = work / time, measured in watts, so doing that 200 J of work in 4 seconds takes 50 W. The work-energy theorem says the net work done on an object equals its change in kinetic energy, which connects forces to the energy transformations between kinetic, potential, and thermal energy. These transformations can be tracked with energy bar diagrams or an energy equation such as initial energy + work done on the system = final energy, where the final energy includes any thermal energy produced by friction.

This explanation is AI-generated and can occasionally be wrong. 🚩 Report