Energy Flashcards
Conservation of energy
Energy cannot be created or destroyed, but can only be transferred from one energy store to another energy store
Kinetic energy store
Moving objects
Chemical energy store
Inside chemical bonds
Thermal energy store
Hot objects
Gravitational potential energy store
Lifting something up
Magnetic energy store
Between two magnets
Electrostatic energy store
Between two charges
Elastic potential energy store
Stretched object
Nuclear energy store
Nuclear reactions
Mechanical energy pathway
When a force is involved
Electrical energy pathway
When electricity is involved
Heating energy pathway
When there is a change in temperature
Radiation energy pathway
By light or other EM waves
Work done is:
When a force moves an object through a distance (same as the transfer of energy)
Calculating work done equation:
W (work done[J])=F (force[N])*S (distance[m])
Examples of work done:
Climbing a flight of stairs Swimming Running 100m Turning the pages of a book A falling parachutist Playing a video game Lifting a weight Writing on a book
Examples of no work done:
Watching TV A spacecraft moving at a steady speed towards the moon Reading a book Driving at a steady speed on a motorway Talking Sleeping, sitting Holding a book
Gravitational potential energy (GPE):
The energy that a body has due to its height above ground
Gravitational potential energy:
GPE (energy[J])=M (mass[kg])*G (gravitational field strength
[m/s2 n/kg])*H (change in height[m])
Kinetic energy:
The energy a moving object has
Kinetic energy store:
KE (kinetic energy[J])=1/2M(mass[kg])*v2(velocity[m/s])
Mass=
Root/KE
—-
1/2V
Efficiency=
Bound/drop * 100 %
Power is
The rate at which work is done
Power(w):
Work done(J)/time(s)
Specific heat capacity:
A property of a material that determines how much energy is required to the raise the temperature of 1kg of the material by 1degree
On earth gravitational field strength is
9.81N/Kg or m/s2
How do biofuels produce electricity
Burning trees animals waste or plants into methane gas manure, waste vegetable oil, straw, nutshells
Give an example of biofuels or where it might be built
Trees, animal waste or plants
Is biofuels renewable
Yes
What are the advantages of biofuels
Renewable so long as trees that are cut down are replaced
Doesn’t add to green house gas or require special equipment
Disadvantages of biofuels
Large areas of land are required to grow enough trees or allow enough animals to graze
How does nuclear power produce electricity
Nucleus of the atoms of uranium or plutonium is unstable and can split into 2 separate atoms with a large release of energy due to large amounts of uranium atoms in the reactor it becomes very hot this thermal energy transferred rest of power station and used produce electrical energy
Give an example of the fuel of nuclear power or where it might be built
The fuel is either uranium or plutonium in sealed cans in the core of the nuclear reactor this is done in nuclear power stations
Is nuclear power renewable
No
Advantage of nuclear power
No greenhouse gases given off as no fuel is burned in a nuclear power station
Much more energy is transferred from each kg of fuel compared to fossil fuels
Disadvantages of nuclear power
Used fuel rods contain radioactive waste which needs to be safely disposed
Possibility of accidental release of radioactive materials
Fossil fuels how does it produce electricity
They are formed from remains of dead plants and animals and are found beneath the earths surface. They burn fossil fuel to transfer them from chemical to heat energy
Example of fossil fuels or where it might be built
Coal,oil and natural gases
Is fossil fuels renewable
No
Advantages of fossil fuels
No green house gases are given off
Much more energy is transferred from each kg of fuel
Disadvantages of fossil fuels
non renewable -emit greenhouse gases e.g. carbon dioxide and sulfur dioxide causing acid rain -finite supply- will run out
Geothermal how does it produce electricity
Cold water is pumped below the ground to the hot rocks beneath the surface
The hot rocks heat the water turning it to steam then the steam is used to create electricity
Geothermal example fuel or where it might be built
In a volcanic area or where the hot rocks are in the earth
Is geothermal renewable
Yes
Advantages of geothermal
Renewable form of energy
No pollution as nothing gets burned
Doesn’t damage/harm the environment
Disadvantages of geothermal
Very few places in the world where this can be done
It is expensive to drill deep underground and lay the pipe
How does solar produce electricity
Generates electricity by using solar cells or to heat water directly in solar heating panels or a solar power tank
Give example of solar fuel or where it might be built
Solar cells or solar heating panels
Is solar renewable
Yes
Advantages of solar
Solar cells:cheap to run, useful where small amounts of electricity are needed e.g. calculators or in remote areas, plenty of sunshine to generate enough power to be useful
Solar heating:heats water that passes through pipes and on a hot day can supply enough hot water for a home to use
Disadvantages of solar
Solar cell:transfers less than 10%sun’s energy that they absorb into electricity, expensive to buy, lots of cells needed
Solar heating panels:can be unreliable in areas often covered in clouds, need to be cleaned regularly to work properly
Tidal how does it produce electricity
Tidal power stations trap water from each high tide behind a barrage the water can then be released into the sea through turbines during low tide, the turbines drive generators which transfer gravitational potential energy from the stored water into electrical energy
Tidal example fuel or where it might be built
Hydroelectric power stations from high tide water
Is tidal renewable
Yes
Advantages of tidal
Renewable form of energy
No pollution as nothing gets burned
Reliable, there are always 2 tides every day
Once it is built it is cheap to run
Disadvantages
Dam/barrage costs a lot to build and can cause local flooding
Can affect nearby habitats of creatures and plants
Wind how does it produce electricity
Wind turbine is an electricity generator at the top of a tower that transfers kinetic energy of the wind into electrical energy. As the force of the wind causes the blades of the turbine to turn around, which turns a generator
Wind give an example of it or where it might be built
Large open spaces such as in the ocean or side of hills with an electricity generator
Is wind renewable
Yes
Advantages of wind
Renewable form of energy
No pollution as nothing gets burned
Turbines are cheap and easy to build
Disadvantages of wind
Create wincing noise when working
Some ppl consider them unsightly
Only works if it is windy!!!
