Back to 'Unit 7: Work and Energy'

Topic outline

  • We define power as the rate at which work is done. We can write this as P = \frac{W}{\Delta t} , where w is work and \Delta t is the duration of the work being done. The unit for power is the watt, W. One watt equals one joule per second.

    Higher power means more work is done in a shorter time. This also means that more energy is given off in a shorter time. For example, a 60 W light bulb uses 60 J of work in a second, and also gives off 60 J of radiant and heat energy every second.