Energy Flashcards
what is the unit of force?
newtons
what is the unit of energy?
joules
what is the unit of distance?
metres
what is the unit of mass?
kg
what is the unit of strength of gravity?
newtons / kg
what is the unit of height?
metres
what is the principle of conservation of energy?
energy is never created or destroyed, only transferred between different energy stores
what is a system?
object or group of objects that interact
what is wasted energy?
energy dissipated to surroundings
when work is done against frictional forces acting on an object, what happens to the temperature?
it rises
what are the 8 energy stores?
- thermal (internal)
- kinetic
- gravitational potential
- elastic potential
- chemical
- magnetic
- electrostatic
- nuclear
what is the thermal (internal) energy store?
the total kinetic and potential energy of the particles in an object/system
what is the kinetic energy store?
energy of a moving object.
what is the gravitational potential energy store?
energy of an object at height.
what is the elastic potential energy store?
energy stored when an object is stretched or squashed.
what is the chemical energy store?
energy stored in chemical bonds, such as those between molecules
what is the magnetic energy store?
energy stored when repelling poles have been pushed closer together or when attracting poles have been pulled further apart.
what is the electrostatic energy store?
energy stored when repelling charges have been moved closer together or when attracting charges have been pulled further apart.
what is the nuclear energy store?
energy stored in the nucleus of an atom.
what are the 4 energy transfer methods?
- mechanical work
- electrical work
- heating
- radiation
what is mechanical work?
force moving an object through a distance
what is electrical work?
charges moving due to a potential difference
how does heating transfer energy?
due to temperature difference caused electrically or by chemical reaction
how does radiation transfer energy?
energy transferred as a wave
what is Specific heat capacity?
the energy needed to increase the temperature of 1kg of a substance by 1 degree celsius
describe the process of conduction
- energy makes the ions in the rod vibrate faster
- as ions in the solid metal are close together, this increased vibration means that they collide with neighbouring ions more frequently
- energy is passed on through the metal by these collisions, transmitting the energy
- more frequent collisions increase the rate of transfer.
what are renewable energy resources?
resources that can be replenished as they are used
what is a a non-renewable energy resource?
a resource which cannot be replenished
what are 2 non-renewable energy resources?
- fossil fuels
- nuclear fuel
what energy store are fossil fuels?
chemical
what energy store is nuclear fuel?
nuclear
what are 2 advantages of using fossil fuels?
- very reliable
- high power output
what is a disadvantage of using fossil fuels?
releases CO2
what are 2 advantages of using nuclear fuel?
- very reliable
- very high power output
what is a disadvantage of using nuclear fuel?
dangerous radioactive waste
list as many renewable energy sources as you can.
- biofuel
- wind
- hydroelectricity
- geothermal
- tidal
- solar
- water waves
what energy store does biofuel use?
chemical
what are 3 advantages of using biofuel?
- reliable
- medium power output
- low negative impact - carbon neutral
what energy store does wind power use?
kinetic
what are 4 disadvantages of wind power?
- unreliable as it depends on weather
- low power output
- take up large areas of land
- birds can be killed
what energy store does hydroelectricity use?
gravitational potential
what are 2 advantages of hydroelectricity?
- very reliable
- medium power output
what is a disadvantage of hydroelectricity?
big areas must be flooded to build dams
what energy store does geothermal use?
thermal
what are 3 advantages of geothermal energy?
- reliable
- medium power output
- very low negative impact
what is a disadvantage of geothermal energy?
not available everywhere
what is the energy store of tidal energy?
kinetic
what are 2 advantages of using tidal energy?
- very reliable
- very high power output
what are 2 disadvantages of using tidal energy?
- hard to harness
- tidal barrages can negatively affect birds feeding on mud flats
what energy store does solar energy use?
nuclear
what is an advantage of solar energy?
low negative impact
what are 3 disadvantages of solar energy?
- very unreliable as dependent on weather
- low power output
- large areas necessary
what energy store do water waves use?
kinetic
what are 2 disadvantages of using water waves for energy?
- unreliable as weather dependent
- low power output
what is an advantage of using water waves for energy?
very low negative impact
what does ‘doing work’ on a system do?
increases the energy stored in a system
what can unwanted energy transfers be reduced by?
- lubrication
- tightening any loose parts
- thermal insulation
how does lubrication reduce unwanted energy transfers?
reduces the friction that produces heat
how does tightening loose parts reduce unwanted energy transfers?
prevents unwanted vibration that wastes energy as sound
how does thermal insulation reduce unwanted energy transfers?
reduces heat loss
