P-1 Energy Flashcards
What is the law of conservation of energy
The law of energy conservation is that energy cannot be created nor destroyed
What happens when a system changes
Energy is transferred
What is meant by work done
Work done is the total amount of energy transferred
What is a closed system
A closed system is a system where energy or matter can neither enter nor leave. The total transfer is always zero
What is a kinetic energy store
- Anything that is moving has energy in its kinetic energy store
- Energy is transferred to this store when an object speeds up. It is removed when an object slows down
- IT depends on an objects mass and speed - greater the greater the store
What is the formula for Kinetic energy store
E(k)= 1/2MV2
where
Energy= 1/2 Mass x speed2
What is meant by gravitational potential energy
- Lifting an object in a gravitational field requires energy
- This causes a transfer of energy to the the gravitational potential energy of the object. The higher- the higher the store
- Dependant on mass, height and strength of gravitational field
What is the equation in gravitational potential energy
E(p)= mph
Where
G.P.E= Mass x height x gravitational field strength
What is the relationship between G.P.E and Kinetic energy as an object falls
- For a falling object with no air resistance
Energy lot from G.P.E = Energy gained in kinetic energy
What is Elastic potential energy
- Stretching or squashing an object causes an energy to transfer energy to its Elastic potential store
- This is directly proportionate until the limit of proportionality is exceeded
What is the equation for Elastic potential energy
E(e) = 1/2 ke2
where
Elastic potential = 1/2 spring constant extension 2
What is specific heat capacity
- Specific heat capacity iOS the aunt of energy needed to raise the temperature of 1kg of substance by 1oc
- it is how hard something is to heat up
What is the equation for specific heat capacity
^E = mc^0
Where
Change in thermal energy = Mass x Specific heat capacity x Temperature energy §
What is power
- Power is the rate of energy transfer or rate of doing work
- Power is measured in Watts
- 1 Watt = 1 joule of energy transferred per second
What are the equations for power
P=E/t where Power= Energy/time
P=W/t where power = Work done/ time
How can unwanted energy transfers be reduced
- Lubrication - This causes a loss of heat energy by friction to take place
What is thermal conductivity
- Thermal conductivity is the measure of how quickly energy is transferred through a material in this way.
- Insulation in houses prevents the loss of heat energy
What is Convection
Convection is when energetic particles move away from hotter to cooler regions
What is efficiency
- Efficiency is the proportion of useful energy transferred out of the overall transfer
- No device can be 100% efficient - except electric heaters - All energy will end up as heat stores
What is the calculation of efficiency
- Efficiency= Useful output energy/ total energy transfer
What are non renewable energy resources
- Non renewable sources of energy are fossil fuels and nuclear fuel. They are typically burnt and will run out
- Some examples are coal, oil and natural gas
what are renewable source son energy
- Renewable energy sources will never run out
- They are typically less damaging to the environment
- They often do not provide much energy or are unreliable
- They include solar, wind., HEP, Bio-fuel- Geothermal
Explain how wind energy works and the pros and cons
- Wind energy is generated by wind turbines
- Each turbines contains a generator. That rotating blades turn the generator and energy is produced
- Cons- Spoil view, noisy, 1500 needs to replace on coal station . initial costs high
- Pros- Natural, renewable, once set up low cost, no fuel costs , no permeant damage to landscape
- Explain how solar cells work and the pros and cons of it are
- Solar cells generate electrical currents from sunlight
- This is then convert into other forms of energy.
- Cons- can’t meet demands, reliant on weather, only useful in some parts of world, initial costs high
- Pros - Free after set up, making use of large rescue, in sunny countries fairly reliable, no pollution
What is Geothermal power and what are the pros and cons of it
- Geothermal power is makings of underground energy sources water poured over and steam generates heat energy
- Pros- Reliable , more can be done to meet demands, can directly heat
- Cons- Aren’t many suitable locations , costs high
What is hydro-eclectic power and what are the pros and cons of it
- Hydroelectric power usually requires the flooding of a dam and water is let out slowly through turbines
- These turbines generate electricity,
- Pros, provides immediate response, no pollution, reliable. no fuel costs
- Cons- Initial cost high , damage to environment.
What is wave power and what are the pros and cons
- Lots of small wave powered turbines are placed around the coast
- The moving turbines generate electricity
-Pros- Minimal running costs, Useful on small islands
Cons- High running costs, ruins sea bed, cannot be done on large scale, high cost
What are Tidal Barrages and what are the pros and cons of them
- Big dams are built across estuaries, with rubies built in
- As the tide comes in and out there forced through the turbine and energy is generated
- Pros- Bo pollution, low maintenance cost, reliable.
Cons- High costs to start, presents boat access, spoils view
What are biofuels
- Biofuels are renewable energy rescues that a created from plant product and animal dung.
- Cons- may not be carbon neutral, cost to refine high , forest has to cleared, Cannot meet energy demands immeditalu
Pros- Renewable, reliable
