Energy Flashcards
what is a system
is an object or group of objects
what is
thermal energy store
kinetic energy store
chemical energy store
gravitonal and elastic energy store.
heat - kinetic and potentail
movement (J)
chemical bnd
postion of gravitonal field and energy held in stetched spring
types of energy store
kinetic, chemical, gravitionl, elastic, thermal
how can energy be transferred
mechanically - strech smt physicallly
electrially- plug smt in socket
heating-light,radition
equation for work done
pwer = work done divide time
kinetic equatio
kinetic energy = 0.5 x mass x (spee)2
equation for grav potentail strength
gravitional potential strenght= mass x grav field streght x height.
what is equation for energy transferedded by power.
power=energy transf / time
in energy transfer what is 1 joule(work done j) equal to.
power of 1 watt. (power w)
Give example that illustrate definition of power.
Light bulb using electricity and power to its work done in producing light.
what can’t energy do?
energy cant be created nor destroyed.
what does dissipated and transferred mean
spreaded out to the surrounding and energy change.
what is a closed system
a system of total energy never changes where no substances can leave or enter.
describe with examples where there are
energy transfers in a closed system, that there is no net change to
the total energry.
An example of phone placed in a jar and trapped with lid on top. As the jar and phone heats up from thermal energy, and transfers around the surrounding in jar, to one point to another in reverse. There is no net change to the total energy as it cannot leave the jar.
describe, with examples, how in all
system changes energy is dissipated, so that it is stored in less
useful ways. (unwanted energy
An example of charging your phone, the electric energy comes from the socket that then flows into the phone in chemical energy store of group particles, and thermal. When using your phone while charging, there is system change as it is dissipated to spread out energy as, it goes screen light energy and speaker for sound energy, in spreading out the rest of unwanted energy.
explain ways of reducing unwanted
energy transfers, examples through lubrication.
Lubrication - to reduce fricition and less thermal. When peddling bike, the wheel and chain gain heat from fricition movement in same reverse direction , makes the heat and hard work. Applying lubrication of oil on the chains bracket, is to reduce friciton and unwated energy transfer due to thermal heat arises by hard work.
Explain ways of reducing unwanted
energy transfers, for example through the use of
thermal insulation
Use of thermal insulation - reduce heat transfer from trapping warm air. Can be, making sure houses are sealed for air not able to pass outside by convenction. to make sure warm air trapped. AND, foam seals aroun door, closing curtains.
describe how the rate of cooling of a
building is affected by the thickness and thermal conductivity of its
walls.
thin walls with high thermal conductivty will conduct thermal energy the quickets and cool down rapidly.
What is conduction
it is how thermal energy travel through soilds.
what is convection
occurs when lot’s of heat enrgy in gas or liquid, moves around and take particles to less thermal energy.
the higher the thermal conductivity of material =…. rate of energy
the higher rate of energy transfer by conduction across material
efficieny answer must alwasy be
a decimal or percentage
effiencieny equation
effieciy = useful power (energy transfer) / input power (energy trnasfer)
what is renewable
energy resource that can be replenished
what is non-renewable
energy resouce cannot be replaced, runs out.
main energy resource
fossil fuel ( coal,oil,gas ), nuclear fuel,biofuel, wind, hydroelectricity, geothermal
types 2 renewable energy + issue
biofuel, trans + elec = larger area needed to grow full crops + expensive.
Water hydroelecricity, ele + gen = large are needed to flood + displace homres.
2 renewable energy + issue
Geothermal, heat+ele+gen= limnated place avaible
Solar, elec+heat+gen= high cost + depend light intensity.
1 type of non-renewable and issue
Oil, trans+heat= burning produce carbon dioxide
2 types of non-renewable and issue
Coal, trans+elec+gen+heat= reliable output + burn produce greenhouse gas.
Gas, trans+elec+gen+heat= Reliable output + burn produce carbon doxide.
Why are some energy resources are more reliable than others and whihc one.
Energy resource in non-renewable in coal and gas, they are reliable output because use of all energy resource in transport, electricity, genertaion, heating than others all use 2 or 3.
what is convection current
process that involve movement of energy from one place to another
convection types to reduce heat
-draught proofing, sealing gaps and opening to prevent cold air enter
-loft insulation
-hot water jacket, lower heat cost
another type of renewable energy
wind, electricity and generation, not reliale+noisy+not prudcue constant source of energy
another type of non-renwale
nuclear fuel,electricuty + genteatin, prouce aioactive source, costly to build, reliable output
