Physics - Energy Flashcards
10 Types of energy
Thermal Kinetic Gravitational potential Elastic potential Chemical Magnetic Electrostatic Nuclear Sound Light
Which of the ten aren’t energy stores ?
Light and sound
Energy can be transferred by work done. What happens ?
When you move an object the energy transfers from one energy store to another. For example when you throw a ball upwards you cause a transfer from chemical to kinetic energy.
When an object falls it also transfers energy. How?
- When something is dropped from a height it’s accelerated by gravity. The gravitational force does work
- As it falls energy from the objects gravitational potential energy store (g.p.e store) is transferred to its kinetic energy store.
- For a falling object when there’s no air resistance :
Energy lost from g.p.e store = Energy gained in kinetic energy store - In real life air resistance acts against all falling objects - it causes some energy to be transferred to other energy stores e.g the thermal store of the object and its surroundings.
Kinetic energy store
Energy is transferred to this store when an object speeds up and is transferred away from this store when an objects slows down.
Gravitational potential energy store
If you raise an object it requires work. This causes a transfer of energy to the g.p.e store of the raised object. The higher the object is lifted the more energy transferred.
Elastic potential
Stretching or squashing an object can transfer energy to its elastic potential energy store. So long as the limit of proportionality has not been exceeded energy in the elastic potential energy store of a stretched spring can be found.
What is limit of proportionality?
On a graph there is a maximum force above which the graph curves, showing the extension is no longer proportional to force.
what does specific heat capacity mean ?
It is really just a fancy way of saying how hard it is to heat something up. Some materials need more thermal energy in their store to increase their temperature compared to others.
Non renewable resources that will run out one day
Coal, oil and gas - the 3 main fossil fuels
Uranium and Plutonium - nuclear fuel
Renewable resources that will never run out
The sun (solar) Wind Water waves Hydro-electricity Bio-fuel Tides Geothermal
Resources that are used for transport
Petrol, diesel and coal - non renewable
Biofuels / biofuels and petrol or diesel - renewable
Resources used for heating
Non-renewable 1. gas 2. Coal 3. Electric heaters Renewable 1. Geothermal 2. Solar water heaters 3. Burning biofuels 4. Electricity generated form renewable resources
Wind power
Put wind turbines on exposed places such as moors or round coasts
Solar cells
Generate electric currents directly from sunlight
