energy Flashcards
what is a system?
an object or group of objects
eg, apple sitting on a table
what happnes when a system changes?
energy is transferred
open vs closed vs isolated systems
open- allows exchange of energy and matter to and from its surroundings
closed- exchange energy but no matter to or from its surroundings
isolated- no exchange of matter or energy to and fro its surroundings
conservation of energy
energy cannot be created or destroyed, it can only be transferred from one store to another
name all 8 energy stores
- kinetic
- gravitational potential
- elastic potential
- magnetic
- electromagnetic- charge
- chemical
- nucleur
- thermal
4 energy transfer pathways- explain
- mechanically- force acted
- electrically- charge through pd
- heating- hotter to colder
- radiation- electromagnetic waves
gravitational field strength of earth
9.8 N/Kg
weight ? force
weight = force
what is specific heat capacity?
the energy required to raise the temperatue of 1kg of substance by 1^c
what is power?
rate at which energy is transferred or the rate at which work is done
what is useful energy
energy that is transferred from store to store and used for an intended purpose
what is wasted energy
energy that is not useful for its intented purpose and is dissapated to the surroundings
how to reduce wasted energy- why
lubrication- reduces friction (heat)
insulation- prevent heat energy dissapating
what factors affect conductivity?
- temperature differenece acroos material- more more
- thickness of materia- thicker less
- thermal conductivity of material- high more
how to improve efficiency?
- reduce friction- lubrication
- reduce electrical resistance- streamlining moving objects
- reduce noise- lubrictation, tightening loose parts
how do all 9 energy resources transfer energy?
- fossil fuels- oil, gas, coal combusted- steam- turbines
- nucleur- heat water to produce steam- turbines
- bio-fuels- plant matter, ethanol, methane
- wind- turbines
- hydroelectric- water stored at height, dams, released- turbines
- tidal- movement of water- turbines
- geothermal- hot rocks underground heat water to produce steam- turbines
- solar- solar cells- use light
- waterwaves- moving water- turbines
what is renewable energy w examples
energy source that is replenished as a faster rate than being used
- solar
- wind
- bio-fuel
- hydroelectricity
- geothermal
- tidal
3 uses of energy resources
- transport (fuel)
- electricty generation
- heating
environmental impacts of energy sources
- mining fossil fules- destroying landscapes
- wind turbines- eyesore
- burning ff- release harmful emissions
- nucleur- radioactive waste
- bio-fuel- land
