ENERGY

Created by

debórah

Cards (30)

equation for kinetic energy
1/2 x mass x (velocity) squared
define specific heat capacity
amount of energy needed to raise 1kg of a substance by 1 degree celsius
energy changes when a ball is thrown upwards then returns to its starting position
upwards: ke converted to gpe
peak: maximum gpe zero ke
downwards: gpe to ke
energy transfers for a bunjee jumper
when falling gpe is converted to ke
ke is converted and stored as epe when cord tightens
at lowest point epe equals gpe
explain why a bungee jumper slows down once the cord begins to stretch
kinetic energy decreases since it is converted to elastic potential energy
since kinetic energy is proportional to velocity squared as ke decreases, so does velocity
examples of chemical stores
food
fuel
batteries
state the law of energy conservation
energy cannot be created or destroyed only transferred
energy changes that occur in the filament light-bulb
electrical energy is transferred into light and heat energy
light is a useful energy form, heat is waste energy
how can the effiency of a system can be increased
reducing waste output (lubrication, thermal insulation)
recycling waste output (thermal waste energy as input energy)
consequence of energy transfer with material with high conductivity
rate of transfer energy through the material is higher than for a material with lower thermal conductivity
factors that affect the rate of cooling on a building
thickness of the walls
thermal conductivity of the walls
three methods of reducing heat loss in a building
double glazing
loft and wall insulation
thicker walls
how can efficiency of mechanical machine with moving parts be improved
lubricate any moving parts to reduce the friction and therefore any energy loss due to heating
how can you improve the efficiency of a radiator
installing metal foil sheets behind the radiator to reflect the heat back into the room rather than it being absorbed into the walls
how can efficiency of boiling water in a pan be improved
by placing a lid on the pan to reduce the heat loss from the top
what is a renewable energy source
an energy source that can be replenished as it is being used up
4 examples of renewable energy sources
wind energy
hydro-electricity
tidal energy
solar energy
example of a non-renewable energy source
fossil fuels
advantages of generating power using gas rather than coal
flexible generation: gas power stations have short start up times so can be switched on/off readily
lower emissions of carbon dioxide
disadvantages of using renewable energy sources
output often determined by external factors
generating power through other means is often more efficient and economonically beneficial
the environmental impacts of burning fossil fuels
carbon dioxide contributes to the greenhouse effect and causes global warming
sulphur dioxide leads to acid rain, which can damage buildings and crops
3 advantages of fossil fuels as an energy source
reliable: not dependent on external factors
can produce large amounts of energy for a given quantity
still relatively abundant, so cost effective
advantages of nuclear power
very large amounts of energy for relatively small amounts of fuel
doesn't release greenhouse gases and so doesn't contribute to climate change
low fuel costs
disadvantages of nuclear power
produces nuclear waste which is harmful to humans
non renewable
risk of nuclear accidents, which have fatal consequences
how does hydroelectric power work
rainwater collects behind a dam
when this water is released it is used to turn a turbine
the turbine turns a generator which produces electricity
disadvantages of biofuels
when plants are burned or decay they release co2
in order to grow biofuels you need to destroy land which can be problematic because:
could have been natural habitats
may involve burning plants growing on it
reduces land available for growing food
advantages of tidal energy sources
do not produce greenhouse gases
reliable
cheap to run as tides ae natural
disadvantages of hydroelectric power
dam may cause flooding
it can cost a lot to install the required infrastructure
advantages of solar panels
dont harm the environment
they are a renewable energy source
can be used in remote areas
social factors which may deter some types of energy production
visual pollution
sound pollution