energy stores and transfers

8 energy stores

• kinetic

• gravitational potential

• elastic potential

• thermal

• chemical

• nuclear

• magnetic

• electrostatic

system

object or group of objects

closed system

system where no energy can be transferred to or from the surroundings. Total energy stays teh same

Work done

Energy transferred when a force moves an object

Unit of energy

J

Unit of one joule transferred per second

Watt (W)

Energy transfer when a moving car slows down

Energy transferred mechanically from the kinetic store of the thermal store of its brakes, some energy dissipated to thermal store of the surroundings

Energy transfer when an e-kettle is used to heat water

electric currents in a kettle transfers energy to the heating element’s thermal store- energy then transferred by heating from the heating element’s thermal store to the thermal store of the water

Energy transfer when a ball is fired using an elastic band

energy transferred mechanically from the elastic store of the elastic band to the kinetic store of the energy- some energy dissipated to the thermal store of the surroundings

energy transfer when a battery powered toy car is used

energy is transferred electrically from the chemical store of the batter to the kinetic store of the toy car- some energy is dissipated to the thermal store of the surroundings

energy transfer when a falling apple hits the ground

energy is transferred from the kinetic store to the apple and dissipated to the thermal store of the surroundings by sound waves