Energy Physics Flashcards
What is the law of conservation of energy?
Energy cannot be created or destroyed, it can only be converted from one form to another.
What is energy measured in?
Joules, J
1 joule is the amount of energy required to heat 1ml of water by 1 degree
When a force moves an object, energy is transferred and work is done. What is the equation to work out work done?
work done = energy transferred
work done = force (N) x distance moved (m)
work done = mass(kg) x gravity (N/kg) x distance (m)
What is the equation to work out the power of something
power (watts) = work done (Joules) divided by time taken (s)
What is the alternate equation to work out power?
power = energy transferred (j) divided by time taken (s)
What is gravitational potential energy (GPE)?
If you move upwards, you work against gravity.
Force = weight = mass x gfs
distance = height
Therefore work against gravity = mgh
GPE = mass(J) x G (10N/kg) x H (m)
GPE = MGH
How does wave energy work?
The sea’s waves have kinetic energy. Machines take advantage of the up and down movement of the waves and this energy can be turned in to electrical energy.
How does tidal energy work?
When the tide is high, the water has gravitational potential energy which we can turn into electrical energy to use in our homes.
Barriers across tidal estuaries can harness the kinetic energy of the sea which drives turbines as the tide comes in.
How does hydroelectric energy work?
Water flowing in a river has kinetic energy. Water stored in a reservoir flows down through pipes to drive turbines which turns generators, producing electrical energy.
Convert the GPE of water in mountain lakes and reservoirs to electricity. GPE of water stored at height gains kinetic energy as it falls down the hill. The kinetic energy of fast moving water drives a turbine –> rotational kinetic energy turns the generator on which gives electrical energy.
How does biomass energy work?
Plants and trees can be grown to provide biomass, containing chemical potential energy which can then be burned to release heat energy. We can also turn it into electrical energy.
How does geothermal energy work?
Some rocks under the Earth’s surface are hot. Cold water pumped through these rocks become hot and turn in to steam which is used to generate electricity.
How does solar energy work?
The Earth gets heat and light energy from the sun all the time which can be transferred into electrical energy to use in homes, using solar cells. It can also be used to heat water for homes using solar panels.
Energy stores x8
Thermal, kinetic,gravitational potential, elastic potential, chemical, magnetic, electrostatic, nuclear
