P1/2/3 : Energy Flashcards
What is energy?
The ability to do work.
How can energy be transferred?
Mechanically - when force acts and makes something move
Electrically - when current flows
By heating - Due to temperature change
By radiation - a wave such as light, sound
What is the conservation of energy?
Energy cannot be created or destroyed, it can only be converted to one form to another.
what is work done and the formula?
transferred energy is the wok done by the force.
WD = Force x Distance
What is kinetic energy and the formula?
the work done to ACCELERATE an object is kinetic energy.
KE = 1/2 X MASS X VELOCITY^2
KE=1/2mv^2
What is the change in gravitational potential energy formula?
GPE= mgh
GPE = Mass x strength of gravity x (change in) height
when is GPE gained and lost?
Gained - object is LIFTED
Lost - object is LOWERED
What is energy store in a spring called? What is the energy transfer when releasing a spring?
Elastic Potential Energy
EPE -> KINETIC
What is power and the formula ?
Power is HOW FAST the energy is transferred.
POWER = WD or energy / time (s)
watts = joules/seconds
What is efficiency and the formula ?
Efficiency is the measure of how much USEFUL energy you get out of an object from the energy you PUT IN .
efficiency = (USEFUL ENERGY OUT/ ENERGY IN) X 100
What is heat energy ?
The random kinetic energy of all the particles inside the object. ( type of kinetic energy - joules)
what is heat capacity ?
Measures how much heat is needed to raise an object’s temperature by 1C degree.
What is the most common reason why energy is lost?
Lost to heat
what is SPECIFIC heat capacity ?
Specific heat capacity is the amount of heat energy needed to raise the temperature of 1KG BY 1C DEGREES.
J/Kg/degrees C
what is renewable energy?
Energy from natural sources that us always replenished, so it never runs out
what is non-renewable energy?
When it has been used, it will be gone forever.
what is the energy transfer when burning fuels?
chemical -> heat/light energy
when a fuel is burned what are the main 2 waste products and why are they harmful?
CO2 / SO2
CO2 - greenhouse gas helps global warming
SO2 - when dissolved in rainwater causes acid rain
ADVANTAGES/DISADVANTAGES of non renewable energy sources?
AD : - cheap
- good for ‘basic demand’
- reliable
- nuclear power station produce little pollution
DIS: - pollution
- runs out
types of renewable energy and the energy transfers.
Tidal - kinetic -> electrical
Wave - kinetic -> electrical
Hydro-electrical power - gravitational -> kinetic -> electrical
Solar panels and thermal towers - electrical -> thermal
Geothermal - heat -> electrical
Biomass - chemical -> heat
Wind - kinetic -> electrical
how its hydro-elecrical power/ geothermal / biomass power obtained?
HYDRO-ELECTRIC - rainwater/river from mountains
GEOTHERMAL - captures heat from ground
BIOMASS - decaying organic matter
2 environmental advantages of using gas fired power station to generate electricity than coal fired ?
Less CO2 released
Less global warming
Less climate change
ad/dis of gas fired power stations?
AD: produce less co2 THAN COAL FIRED
- reliable
- produce large amounts of power
DIS: - unattractive
- expensive
- non renewable
ad/dis of biofuels?
ad: can be easily grown on farmland
dis :requires large areas of land to grow cops
wind turbines ad/dis?
ad: dont need many
- less pollutants
dis : unreliable
- ugly/noisy
geothermal ad/dis?
ad : reliable
- geothermal station are small
dis : harmful gases underground
- not suitable for some places
ad/dis of hydroelectric?
ad : reliable
- produce alot of energy
- no pollution
DIS : can flood areas–> destroy habitats
how does an uncharged object become positively charged?
negatively charged electrons are transferred from a neutral object
