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Energy stores and transfers - Coggle Diagram
Energy stores and transfers
Types of energy stores
Kinetic - Anything moving
Thermal - The hotter an object, the more thermal energy
Chemical - Anything that releases energy from a chemical reaction
Gravitational potential - anything with a mass inside a gravitational field
Elastic potential - Anything stretched or compressed
Electrostatic - Anything with electrical charge interacting with another electrical charge
Magnetic - A magnet interacting with another magnet
Nuclear - Atom nuclei have energy which can be released in reactions
Energy transfers
A system is an abject you are interested in
Closed systems - neither matter nor energy can enter/ leave
When a system changed, energy is transferred between different energy stores
Ways energy can be transferred
Mechanically - an object moving
Electrically - a charge moving through a pd
Heating - energy transferred from a hotter to a colder object
Radiation - energy transferred from light/ sound waves
Kinetic energy
Kinetic energy = 1/2 X mass X Velocity ^2
Energy is transferred to the source when it gains speed
Energy is transferred away from the source when it looses speed
Power
Power = Work done / time
Power = Energy / time
Measured in Watts (W)
The rate of energy transferred or the rate of doing work
Work done = force X distance
Potential energy stores
Elastic potential energy
Epe = 1/2 X spring constant X extension^2
Squashing or compressing an object transfers energy to its elastic potential store
Gravitational potential enegry
GPE = mass X field strength X height
When something falls, energy is transferred from its gpe store to kinetic energy
Specific heat capacity
The amount of energy needed to raise the temperature of 1kg of a substance by 1 degree
energy = mass X SHC X Temperature change
Efficiency
Efficiency = useful output energy / total input energy
Efficiency = useful power output / total power input
The less energy wasted, the more efficient the device is said to be
No device is 100% efficient except electric heaters
Increasing efficiency
Reducing waste output (lubrication, thermal insulation)
Recylcing waste output (Absorbing thermal wast and recylcing as input energy)
Conduction and convection
Conduction
The process where vibrating particles transfer energy to neighbouring particles
Thermal conductivity is a measure of how quickly energy is transferred through a material
Materials with a high thermal conductivity transfer energy between the particles quickly
Heated particles have more energy to collide
Happens in solids
Convection
Convection occurs when the more energetic particles move from the hotter regions to the cooler regions and take their energy with them
Can happen in gasses and liquids