power and work done

Cards (29)

  • What is the focus of today's video?
    Understanding power and its calculations
  • How many definitions of power are there?
    Two definitions
  • What is the first definition of power?
    Rate at which energy is transferred
  • What is the equation for power based on energy transferred?
    Power = energy transferred / time
  • What is the second definition of power?
    Rate at which work is done
  • What is the equation for power based on work done?
    Power = work done / time
  • What does "work done" refer to?
    Energy transferred using a force
  • If you push a car down the road, what is the energy referred to as?
    Work done
  • How is electrical energy transferred from a plug socket to a phone referred to?
    Energy transferred
  • What unit is power measured in?
    Watts
  • What units are energy transferred and work done measured in?
    Joules
  • What unit is time measured in?
    Seconds
  • How much energy does the left lamp transfer?
    1200 joules
  • How long does the left lamp take to transfer energy?
    20 seconds
  • What is the power of the left lamp?
    60 watts
  • How much energy does the right lamp transfer?
    1500 joules
  • How long does the right lamp take to transfer energy?
    30 seconds
  • What is the power of the right lamp?
    50 watts
  • Which lamp is more powerful?
    The left lamp
  • How much energy is transferred by an 1100 watt microwave in three minutes?
    198,000 joules
  • How do you rearrange the energy transferred equation?
    Energy transferred = power × time
  • How do you convert three minutes to seconds?
    180 seconds
  • What is the energy transferred when an 1100 watt microwave is on for three minutes?
    198 kilojoules
  • How much work is done to push a car down the street?
    9 kilojoules
  • How much time is taken to do the work of pushing the car?
    20 seconds
  • What is the power used when pushing the car?
    450 watts
  • What are the key equations for power?
    • Power = energy transferred / time
    • Power = work done / time
  • What are the differences between energy transferred and work done?
    • Energy transferred: No force or movement
    • Work done: Involves force moving an object
  • What are the units for power, energy transferred, work done, and time?
    • Power: Watts
    • Energy transferred: Joules
    • Work done: Joules
    • Time: Seconds