energy Flashcards
8 energy stores
Nucleur
Electrostatic
Chemical
Kinetic
Thermal
Elastic potentail
Gravitaional potentail
Magnetic
4 energy transfers
mechanical
electrical work
heating (electrical/chemical)
radiation
work done definition
can be done when …
ebergy that has been transfered
current flows or force of a moving object
energy efficiency
some input is usually wasted by being transferred toa useless energy store
less energy that is wasted the more efficient the device is
effeciency equation
efficiency=useful output/total input
power defenition
equation
rate at which energy is transferred
power=work done/time p=w/t
1w=1j/s
7 types of renewable energy
bio fuel wind hydro electricity geothermal tides sun water waves
fossil fuels
very reliable
provide most of countries electricity
opperate almost continuously
cheap but expensive to build and decommission
when is energy transferex to / away from kinetic store
energy is transfered to store when an object speeds up
energy is transfereed away when object slows down
kinetic energy equation
2
kenetic energy=1/2 mass x speed
2
Ek =1/2MV
gravitation potentail
raised objects store energy in gravitational potentail energy
gravitational potential equation
gpe = mass x gravitational feild strength x height
Ep = mgh
elastic energy
stretching or squashing an object can transfer energy to its elastic potentail energy store
elastic energy equation
2
=1/2 spring constant x extension
2 Ee = 1/2ke
specific heat capacity
qmount of energy needed to raise temperature of 1kg of substance by 1•
