conservation of energy and power Flashcards
what is the conservation of energy
energy is never created or destroyed
what happened when energy is transferred between stores
not all the energy is transferred usually into the store, some is dissipated
what is dissipated energy
wasted energy
why is dissipated energy called wasted energy
because the energy is stored in a way its not useful
why does your phone feel warm after you using it for a long time
energy is usefully transferred from the chemical energy store of the battery in the phone
some energy is dissipated in this transfer to thermal energy of the phone
describe energy transfers for closed systems
(what happens when a cold spoon is dropped into an insulated flask of hot soup)
the flask is a good thermal insulator, so the spoon and soup form a closed system
energy is transferred from the thermal energy of soup to the useless thermal energy of the spoon
energy transferred has occurred but no energy has left
what is the rate if doing work
how much per second
what is power measured in
watts
how much does 1 watt equal to
1 joule of energy transferred per second
how do you calculate power
energy transferred or work done / time
