Calculating power

• What should you be able to describe by the end of the video?

  What's meant by power
• How can power be calculated?

  Using either energy or work done
• What is the definition of power?

  Power is the rate at which energy is transferred or the rate at which work is done
• What is the formula for power in terms of energy transferred?

  Power in watts = energy transferred in joules / time in seconds
• What is the unit for power?

  The unit for power is the Watt
• What is the formula for power in terms of work done?

  Power in watts = work done in joules / time in seconds
• What is the symbol for Watt?

  The symbol for Watt is capital W
• How do you calculate the power of a bunson burner transferring 250,000 Joules of thermal energy in 500 seconds?

  • Power = energy transferred / time
  • Power = 250,000 J / 500 s
  • Power = 500 W
• If 40,000 Joules of work is done by the brakes in 5 seconds, what is the power of the brakes?

  The power of the brakes is 8,000 Watts
• How much energy transfer corresponds to one Watt?

  One Watt is an energy transfer of one Joule per second
• How do you calculate the power of a bunson burner transferring 180,000 Joules of thermal energy in 500 seconds?

  • Power = energy transferred / time
  • Power = 180,000 J / 500 s
  • Power = 360 W
• How do you calculate the power of Motor A transferring 500 Joules of energy in 40 seconds?

  • Power = energy transferred / time
  • Power = 500 J / 40 s
  • Power = 12.5 W
• How do you calculate the power of Motor B transferring 500 Joules of energy in 60 seconds?

  • Power = energy transferred / time
  • Power = 500 J / 60 s
  • Power = 8.3 W (to one decimal place)
• Where can you find more questions on calculating power?

  You can find more questions in the vision workbook
• What should you be able to do by the end of the video regarding power?

  You should be able to describe and calculate power using energy or work done