Power is the rate at which work is done. Its nice to know that work is being done, but it is better to know how quickly it is being done. The formula for power is:
Power is equal to the work done divided by the time it took to do that work. Power gets its own special unit. Joules (the unit of work) divided by time is equal to a watt. That’s right. Same one as on the light bulb. Incidentally, there is another way to write the equation for power that pops up occasionally. Since work equals force times distance, you can write power as: P=Fs/t. Now distance divided by time is equal to velocity, so you can also write power as:
Power is equal to the force times the velocity. This formula usually applies to engines. The force is the force that the engine exerts to make the wheels turn and the velocity is the velocity that the car moves at.