energy i

mass x gravitational field strength x change in height

10N/kg

1/2mv^2

A system where there is no net change to the total energy of the system

Energy cannot be created or destroyed, it can only be transferred from one store to another

Kinetic - moving objects
GPE - objects gain energy when lifted above ground
Elastic potential - objects have energy if they are stretched
Electrostatic. - Objects with charge interacting with one another
Magnetic - magnetic interaction
Chemical potential - objects can release energy in chemical reactions
Nuclear - atomic nuclei release during nuclear reactions
Thermal - all objects have energy in thermal store

Mechanical work - When a force acts on an object
Electrical work - A charge moving through a potential difference
Heating - energy transferred from hotter to colder object
Radiation - Energy transferred by electromagnetic waves

A flow diagram that represents the total energy, the wasted energy and the useful energy of an appliance.

Chemical store of body - kinetic store of ball - GPE of ball

Chemical store of fuel - kinetic store of car - thermal store of wall and air

Mains - thermal store of element (electrical work) - thermal store of water

Lubrication (reduces friction)
Insulation (prevents heat from dissipating)

How well the insulator conducts heat
How thick the insulation is

The temperature difference across the insulation
The thickness
The conductivity

Efficiency= Useful energyorpower output/total energyorpower input

-Measured in %

Reducing friction (bearings or lubrication)
Reducing electrical resistance (or lowering current)
Reducing air resistance (streamlining objects or posture)
Reducing noise (tightening or lubricating parts)

Burning fossil fuels heats water, producing steam which turns turbines

Nuclear fuel is reacted, producing heat which creates steam

Plant matter, ethanol or methane can be produced and used as a fuel instead of fossil fuels

Wind turbines can be used to produce energy

The GPE of water stored in reservoirs turns turbines

A dam is used to trap seawater at high tide, which can then be released through a turbine generating electricity

Heat from underground can be used to create steam, which spins turbines

Photovoltaic cells can use light to create electricity or thermal radiation from the sun warms water in black pipes

Wave machines use the kinetic energy from the rise and fall of ocean waves to drive electricity generators

An energy source that is replenished at a faster rate than the rate at which it is used

Reliable. Can produce large amounts of energy at short notice

Not renewable
Produces greenhouse gases and pollution

Reliable. Produces no pollution. Very high energy density

Dangerous radioactive waste taking thousands of years to decay. Not renewable

Renewable. The carbon dioxide produced is balanced by the carbon dioxide absorbed while producing

Takes up land and consumes rescources needed for food production

Renewable. No greenhouse gases or pollution. Land still used for farming

Not reliable. Turbines noisy and ugly. Not everywhere is suitable

Renewable. Reliable and produces large energy amounts at short notice. No pollution or greenhouse gases

Involves flooding large areas, destroying habitats

Renewable. Tides are very predictable. Large amounts of energy at regular intervals

Very few suitable locations. Causes environmental harm to estuaries and disrupts shipping

Renewable. Reliable. Stations are small

Release of harmful gases. Very few locations work

Renewable. No greenhouse gases or pollution p. Good for producing energy in remote places

Not reliable. Uses up farmland