Physics- Calculating power

• Power


  The rate at which energy is transferred or the rate at which work is done
• Calculating power


  1. Energy transferred in joules / Time in seconds

  2. Work done in joules / Time in seconds
• Watt


  Unit of power, equal to an energy transfer or work done of 1 joule per second
• Calculating power of Bunsen burners

  • Left burner: 250,000 J in 500 s = 500 W
  • Right burner: 180,000 J in 500 s = 360 W
• Calculating power of car brakes

  • 40,000 J of work done in 5 s = 8,000 W
• Calculating power of motors

  • Motor A: 500 J in 40 s = 12.5 W
  • Motor B: 500 J in 60 s = 8.3 W