Energy Flashcards
what is a system?
an object or group of objects
kinetic energy equation
1/2 x mass(kg) x velocity^2(m/s)
what is elastic potential ?
type of energy stored in a spring when it’s stretched.
what is specific heat capicity?
energy required to raise the temperature of 1kg of substance by 1oC.
energy calculation in terms of shc
Energy = mass x specific heat capacity x temperature change
What is power?
Rate at which energy is transferred or the rate at which work is done.
what equation links power, work done and time.
power = work done / time
law of conservation of energy
energy cannot be created or destroyed, only transferred
what happens when energy is dissipated in system changes?
stored in less useful ways, often described as being ‘wasted’
name and explain two ways of reducing energy waste
lubrication : oil in motor reduces friction so less energy is lost (as heat) through friction Thermal insulation : double glazing , less useful thermal energy lost
efficiency calculation
Efficiency = useful energy ouput /total energy input or Efficiency = useful power output/total power input
how to increase efficiency
reducing waste ouput or recycling waste output
what are the two types of energy sources ?
Non -renewable and renewable.
name two non-renewable sources of energy
nuclear fuel ,fossil fuels(coal,oil,gas)
what type of energy source do we get most of our electricity from ?
Non- renewable
name 7 renewable energy sources
wind , water wave, biofuel, geothermal, Solar, hydroelectricity and tidal.
negative of using nuclear fuels as an energy source ?
possible chance of nuclear meltdown -would be catastrophic. Requires lots of clean up due to waste , expensive.
explain why renewable energy is not always reliable .
wind depends on weather and solar doesn’t work in bad weather or at night .
difference between renewable and nonrenewable energy sources ?
renewable can be replenished as its used. non renewable cannot be replenished.
explain why in non renewable energy sources is better for large scale energy supplies ?
larger amount of output per kilogram compared to renewable
three main energy uses ?
transport, heating and electricity generation
