98 Views

Download Presentation
## Measuring Energy Part 1

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -

**Measuring Energy Part 1**Newtons, Joules, Watts**Energy Use in Canada**• Canadian households used 1,425 petajoules of energyin 2011(StatsCan) • 1 petajoule is approximately the amount of energy needed to run the TTC subway for one year**Newton (N)**• SI unit of FORCE • Force is a push or pull against an object • 1 Newton is the amount of force needed to accelerate a mass of 1 kg by 1 meter/s2 N = kg x m/s2 A newton will move 1 kg of weight • one meter in the first second, • 2m in the second second • 3m in the third second**Newton (N)**1 KG 1 KG 1 KG 1 KG 1 KG 1 KG Time 1 Second 2 Seconds 3 Seconds**Joule (J)**• SI unit of energy and work • Energy is the ability to do work • Work is the energy transferred when a force moves an object • 1 joule is the work done/energy transferred when 1 newton of force moves an object 1m. J = N x m (N=newton, m=meter) One joule equals the energy needed to lift an apple from the floor to the tabletop, about 1m.**Watt (W)**• The SI unit of power • Power is the rate at which work is done • One watt is equal to 1 joule of energy produced per second W = J/s (j=joule, s=sec)**Watt hours (Wh)**• Light bulbs are rated according to the power they use • this is measured in Watt hours (Wh). Since there are 3600 (60 x 60) seconds in an hour one watt hour = 3 600 joules of energy • A 20 watt lightbulb uses 20 watts of power in an hour. • A 20 watt bulb uses 3 600 X 20 = 72 000 joules of energy**Kilowatts (KW)**• 1000 Watts is a kilowatt (KW) • A kilowatt hour (KWh) is equal to 1000 watt hours (Wh) One KWh = 1000 watt hours 1000 watt hours = 1000 x 3 600 = 3 600 000 joules