Energy stores and systems, kinetic and potential energy stores, Specific heat capacity,
Energy stored and systems
Energy is transferred between stores
1) Thermal energy stores 2) Kinetic energy stores 3) GP energy stores 4) EP energy stores 5) Chemical energy stores 6) Magnetic energy stores 7) Electrostatic Energy stores 8) Nuclear energy stores
Energy is transferred mechanically, by doing work, by moving charges, by heating or radiation
When energy is transferred to and object the energy is stored in one of the object's energy stores
Systems
A system is a single object or a group of objects that you're interested in
When a system changes, energy is transferred. It can be transferred into and away from the system
Closed systems are systems where neither matter nor energy can enter or leave. The net change in the total energy of a closed system is always 0
Kinetic Energy stores
Kinetic energy stores depends on the object's speed and mass. The greater the mass and the faster it's going, the more energy will be taken to the KE store
KE = 1/2 x mass x (speed)2
Anything that is moving has kinetic energy in its kinetic energy store. Energy is transferred to this store when an object speeds up and is transferred away from this store when an object slows down
GPE stores
GPE store depends on Height, mass and strength of the gravitational field strength
GPE = Mass x height x GFS
Lifting an object in a gravitational field requires work.
Elastic Potential energy
Stretching or squashing an object can transfer energy to its EPE store
EPE = 1/2 Spring constant x (Extension)2
Specific heat capacity
Materials that need to gain energy for thermal energy stores to warm up also transfer energy when they cool down again
Specific heat capacity is the amount of energy needed to raise the temperature of 1kg of a substance by 1˚C
Thermal energy store needs more energy to be transferred of some materials to increase their temperature than others
Thermal energy change = Mass x Specific heat capacity x temp change