Conservations of energy Flashcards
Law of conservation of energy
Energy can be stored, transferred between stores and dissipated - but it can never be created or destroyed
The total amount of energy of a cosed systen has no net change
Kinetic
Anything moving has energy in its kinrtic energy store
Thermal
Any object - the hotter it is, the more energy it has in this store
Chemical
Anything that releases energy by a chemical reaction
e.g. food, fuels
Gravitational potential
Anything in a gravitational field
e.g. anything that can falls
Elastic potential
Anything streched like springs or rubber bands
Electrostatic
e.g. two charges that act or repel each other
Magnetic
Two magnets that attract or repel each other
Nuclear
Atomic nuclei releases energy from this store in nuclear reaction
What is a closed system
A system where energy and matter can’t enter or escape
Mechanically
A force acting on an object
e.g. pushing, streching
Electriacally
A charge doing work
e.g. charges moving around a circuit
By heating
Energy transferred from hottor object to colder object
By radiation
Enegy transferred by waves
e.g. energy from the sun reaching the earth by light
What does lubrication mean
Reduces energy lost
Such as putting oil on a bike to reduce friction which will decrease the amount of energy going to the thermal store
What is a open system?
An open system is where the matter of the system (single object) can exchange energy with the outside outside world
This means that an open system can lose or gain energy as it interacts with the outside world
What is a closed system?
can energy be transferred in the system
A closed system is seperate from the outside world, matter or energy can’t leave
Energy can be transferred within the system but the overall change is zero
What is meant by work done?
Work is done by a force when the object moves in the direction of the force
Work done is the amount of energy transferred (measured in Joules)
