Power is the measure of how fast work is done.
Power is the rate at which work is done and the rate at which energy is used.
An interesting calculation is the average power output of a human being. This can be determined from the amount of energy we consume in a day in the way of food. In other words, on the average, we're just a little brighter than your average light bulb. Calculating power from speed Power is work over time, and work is force multiplied by distance. Here's an example of when you might use this.