Energy Transfers Flashcards
(32 cards)
what is a system (in energy transfers)?
an object or a group of objects
state the changes in energy stores when an object is projected upwards
- from the kinetic store
- to the gravitational potential store
state the changes in energy stores when a moving object hits an obstacle
- from kinetic energy
- to thermal and sound energy
state the changes in energy stores when an object is accelerated by a constant force
- from chemical, thermal or electrical
- to kinetic
state the changes in energy stores when a vehicle slows down
- from kinetic
- to thermal and sound
state the changes in energy stores when bringing water to a boil in a kettle
- from electrical
- to thermal
explain the conservation of energy
- energy can be transferred usefully, stored or dissipated
- it cannot be created or detroyed
- the total energy in a system does not change
3 examples for how the amount of wasted energy in a system be reduced?
- thermal insulation- when a house is heated, energy can be transferred through windows doors and walls so the house is insulated or the windows are double glazed
- lubrication- energy when you ride a bike can be lost to friction from the chain which can be stopped by oiling the chain
- streamlining- when planes travel through air they experience air resistance so they are given pointy noses and long bodies
explain the relationship between thermal conductivity and energy transferred
The higher the thermal conductivity of a material the higher the rate of energy transfer by conduction across the material
describe how the rate of cooling of a building is affected by the thickness and thermal conductivity of it’s walls
- The thicker the walls of a building, the slower its rate of cooling
- The lower the thermal conductivity of a building, the slower its rate of cooling
equation for efficiency
useful power output/ total power input
suggest and explain ways to increase the efficiency of an intended energy transfer
- thermal insulation- when a house is heated, energy can be transferred through windows doors and walls so the house is insulated or the windows are double glazed
- lubrication- energy when you ride a bike can be lost to friction from the chain which can be stopped by oiling the chain
- streamlining- when planes travel through air they experience air resistance so they are given pointy noses and long bodies
what are the main renewable energy resources? (7)
- wind
- hydroelectricity
- geothermal energy
- biofuel
- tides
- sun/ solar
- water waves
what are the main non-renewable energy resources? (2)
- fossil fuels- coal, oil, and natural gas
- nuclear fuels
what is a renewable energy resource?
resource that is being (or can be) replenished as it is used
which energy resources can be used for transport?
- fossil fuels
- biofuel
which energy resources can be used for electricity generation?
all of them:
* fossil fuels
* nuclear fuels
* biofuels
* wind
* hydroelectricity
* geothermal
* tides
* sun
* water wvaes
which energy resources can be used for heating?
- fossil fuels
- biofuels
- geothermal
- sun
why are some energy resources more reliable than others? give examples
- non-renewable sources are the most reliable as they can be used at any time
- renewable sources normally depend on the weather
- e.g. if there is no wind, or no sun (night-time), or no waves then no electricity can be generated
what environmental impact do fossil fuels have?
they release CO2 which causes global warming
what environmental impact do nuclear fuels have?
radioactive waste (needs to be disposed of safely)
what environmental impact do biofuels have?
little to no effect because they are carbon-neutral BUT growing them can take up land that could be used for farming
what environmental impact does wind energy have?
takes up large areas that could be used for farming and windmills change the landscape visually
what environmental impact does hydroelectricity have?
local habitats are affected by the large areas that need to be flooded to build dams
