Chapter 15 Power
just like the word “work”, power has a different meaning in the science world power tells you how fast work is being done
Power the rate at which work is done, or the amount of work per unit of time
How to Calculate Power Power = Workor Force*Distance TimeTime Units are defined as a watt (W) or a joule/second
Watt the watt is used to express electrical power examples = light bulbs & appliances
Watt a 50-watt light bulb does work at a rate of 50 joules per second a 110-watt light bulb has more power than a 50- watt light bulb
Kilowatts (kW) large quantities of power are measured in kW 1 kW = 1000 W this is how power in your home is measured
Remember the Procedure Write the equation Figure out what is being asked – what are you solving for? Determine what information is given Plug & Chug – don’t forget the units!
Problem A small motor does 4000 J of work in 20 seconds. What is the power of the motor in watts?