Topic P1 - Energy Flashcards
What are the 8 types of energy store?
KG CEMENT
1) Kinetic
2) Gravitational Potential
3) Chemical
4) Elastic Potential
5) Magnetic
6) Electrostatic
7) Nuclear
8) Thermal
What are the 4 types of energy transfer?
HERM
1) Heating
2) Electrical (work done by moving charges)
3) Radiation (e.g light or sound)
4) Mechanical (a force doing work)
Work done = ..?
Work done = energy transferred
System definition
A single object or a group of objects
If an arm throws a ball up where does the energy transfer too and from?
Chemical energy store of arm
- Arm moves up
Kinetic energy store of ball and arm
For energy transfers in five different systems, read page 76.
^^
Kinetic energy formula
K.E. = 1/2 mv²
m = mass v = speed (velocity) K.E = kinetic energy
What is kinetic energy measured in?
Joules ( J )
What is mass measured in, in physics?
Kilograms (kg)
What is speed measured in?
m/s
Gravitational potential energy formula
E.P = mgh
m = mass g = gravitational field strength h = height E.P = gravitational potential energy
What is gravitational field strength measured in?
N/kg
What is height measured in?
meters (m)
What is conservation of energy?
Energy can be transferred usefully, stored or dissipated, but not created or destroyed.
What is a closed system?
No energy (or matter) is transferred in or out of the system, so there is no overall change in total energy.
What is specific heat capacity?
The amount of energy needed to raise the temperature of 1kg of a substance by 1 degree Celsius.
Power definition
Rate of energy transfer (or rate of doing work)
One Watt (W) = one joule…?
One Watt (W) = one joule of energy transferred per second.
What are the 2 Power formulas?
P = E/t P = W/t
E = energy transferred ( J ) P = Power (W) t = Time (s) W = Work done ( J )
What is work the measure of?
The measure of energy transfer when as force moves an object through a distance.
Work done is equal to…
Work done is equal to energy transferred.
What is energy transfer measured in?
Joules
What is work done measured in?
Joules
What is power measured in?
Watts
Why do 2W motors lift mass faster than a 1W motor?
2W motor transfers more energy per second than 1W so the mass lifts faster
What 2 ways can efficiency be measured by an equation?
1). Useful output energy transfer
Efficiency = ————————————
Total input energy transfer
2). Useful power output
Efficiency = ————————————
Total power input
No device is 100% efficient, true or false?
True
Conduction definition
Process where vibrating particles transfer energy to neighbouring particles.
Convection definition
Where energetic particles move from hotter to cooler regions.
How can the efficiency of useful energy transfers be increased?
Through lubrication and thermal insulation.
How does thermal insulation reduce unwanted energy transfers?
Reduces unwanted energy transfers by heating.
How does lubrication help reduce energy dissipation?
Frictional force is reduced
What 2 ways can you decrease how quickly a building cools?
1) Increase the thickness of its walls
2) Make walls out of material with lower thermal conductivity.
The higher a materials thermal conductivity, the faster…
the faster it transfers energy by conduction.
Non-renewable energy resources meaning?
Energy resources that will run out one day.
Renewable energy resources meaning?
Energy resources that will never run out.
Are fossil fuels renewable or non renewable?
Non-renewable
What are 3 fossil fuels?
1) Coal
2) Oil
3) Natural Gas
What is coal used for?
- Burned for heating
- Used to power steam trains.
What is oil used for?
To make fuel for cars
What is gas used for?
Used to heat water that is then pumped into radiators
How does burning fossil fuels negatively effect the planet?
Burning fossil fuels releases CO2 contributing to global warming.
Burning coal and oil releases sultry dioxide, causing acid rain
Is nucleus power renewable or non-renewable?
Nucleus power is non-renewable
How does nuclear power generate electricity
Nuclear fuel undergoes fission in nuclear reactors, generating electricity.
Why is nuclear power bad?
Nuclear waste is dangerous, difficult and expensive to dispose of
Carries the risk of a major catastrophe.
Is wind power renewable or non-renewable?
Renewable
How do wind power work?
Wind turns wind turbines, generating electricity.
Why is wind power good and bad?
Produce no pollution when in use
Noisy
Spoil the view
Are wind turbines reliable or unreliable?
Unreliable, reliant on wind speed, stops turning when wind is too strong or not present.
Is solar power renewable or non-renewable?
Renewable
How does solar power work?
Solar cells generate electric directly from sunlight.
Why is solar power a good source of electricity?
Produces no pollution when in use.
Is solar power reliable or not reliable?
Reliable in daytime, especially in sunny countries
What are solar water heaters?
Solar water heaters use the sun to heat water which is then pumped into radiators.
Is geothermal power renewable or non-renewable?
Renewable
How does geothermal power work?
Energy from thermal energy stores of underground hot rocks used to generate electricity.
Why is geothermal power good?
Does very little environmental damage
Is geothermal power reliable or not reliable?
Reliable
What are geothermal heat pumps used for?
To heat buildings
Is hydro-electric power renewable or non-renewable?
Renewable
How does hydro-electric power work?
Big dams, built in valley, fill up with water.
Water allowed out through turbines, generating electricity.
Is hydro-electric power reliable or non-reliable?
Reliable (unless there is drought)
Why is hydro-electric power good and bad?
Produce no pollution when in use.
Rotting plants (from flooded valley) release methane and CO2 contributing to global warming.
Is wave power renewable or non-renewable?
Renewable
How does wave power work?
Waves move up and down.
Air forces thorough turbines.
Electricity is generated.
Why is wave power good and bad?
Produce no pollution when in use
Disturbs habitats of sea animals
Spoils the view
Is wave power reliable or unreliable?
Unreliable - waves depend on wind
Are tidal barrages renewable or non-renewable sources of power?
Renewable
How do tidal barrages work?
Tide comes in
Water builds behind the dam
Water allowed out through turbines
Electricity generated
Why are tidal barrages good and bad?
Produce no pollution when in use.
Disturbs habitats of nearby wildlife.
Spoils the view.
Are tidal barrages reliable or unreliable?
Reliable - tides are predictable
Are bio-fuels renewable or non-renewable?
Renewable
How are bio-fuels made?
Made from plant products or animal dung.
How do bio-fuels generate electricity?
Bio-fuels are burned to generate electricity.
Why can bio-fuels be bad for the environment?
In some regions, large areas of forests destroyed to grow bio-fuels, so species lose natural habitats
What can bio-fuels be used for?
Burned for heating
Used as fuel in some cars
Is bio-fuel reliable or unreliable?
Reliable
What are the trends of energy use from 1900-2000 and 2000 onwards?
1900-2000
Electricity use increased as:
- population grew, people began to use electricity for more things
2000 onwards
Electricity use decreasing as:
- appliances are more efficient
- people are more careful with amount energy use
What are the 3 reasons why we are increasing use of renewables?
1) Burning fossil fuels is very damaging to the environment.
2) We need to learn how to get by without non-renewables before they run out.
3) Pressure on governments have led them to introduce renewable energy targets.
How is change in energy sources limited?
Limited by:
- cost
- social issues
- ethical concerns
- political issues
Power is..
Energy per second
Potential difference is =
Potential dif. = current x resistance
