P1
Energy stores
specific heat capacity
Efficiency
Stores and systems
Kinetic and potential energy
energy is transferred between stores
when a system changes energy is transferred
there are 8 energy stores
they can be changed by heating or doing work
Kinetic energy is increased when an object is moving. it also has energy transferred when an object is moving quickly to its store and out when it slows down
gravitational potential energy is when an object has been lifted and you work out how much energy it takes to get back down to ground
1/2xmxv2
mxgxh
Different materials have different heat capacities
spc=change/tempxmass
specific heat capacity is the amount of energy required to raise 1kg 1 degrees centigrade
most energy transfers waste some energy
useful devices are only useful if they transfer energy from one store from the other
you can change that by lubricating or insulating objects
less energy is wasted when a device is more efficient
e=useful output energy/total input energy transfer
you can work out efficiency if you know the power input and output
efficiency useful power output/total power input