iGCSE Edexcel Physics Energy Stores & Transfers

conservation of energy

energy can never be created or destroyed - it's only converted from one store to another

what is efficiency?

a measure of how good a device/appliance is at converting energy from one store into a useful store

formula for efficiency

useful energy output /total input energy (x 100%)

formula for kinetic energy

1/2 x mass(kg) x v^2(m/s)

formula for work done

force(N) x distance moved in the direction of the force (m)

formula for gpe

mass(kg) x change in height (m) x gravitational field strength (N/Kg or m/s^2)

what are the energy stores?

1. magnetic

2. kinetic

3. nuclear

4. electrostatic

5. chemical

6. elastic potential

7. gravitational potential

8. thermal (internal)

what are the energy transfers?

1. by mechanical working (mechanically)

2. by electrical working (electrically)

3. by heating

4. by radiation (light (infrared) + sound)