Energy

The main stores of energy are: k[blank_start]inetic[blank_end] g[blank_start]ravitational[blank_end] p[blank_start]otential[blank_end] ch[blank_start]emical[blank_end] e[blank_start]lastic[blank_end] p[blank_start]otential[blank_end] n[blank_start]uclear[blank_end] i[blank_start]nternal[blank_end] el[blank_start]ectrostatic[blank_end] m[blank_start]agnetic[blank_end]

The Internal Store is the [blank_start]sum of the kinetic[blank_end] and (chemical) [blank_start]potential energy[blank_end] in an object's particles. Temperature is [blank_start]a measure of the energy[blank_end] in an object's particles.

Kinetic Energy = 1/2 x [blank_start]mass[blank_end] x [blank_start]velocity^2[blank_end] Change in Gravitational Potential Energy = mass x [blank_start]gravitational field strength[blank_end] x [blank_start]change in height[blank_end] Elastic Potential Energy = 1/2 x [blank_start]Spring Constant[blank_end] x [blank_start]extension^2[blank_end]

Conservation of Energy means that energy cannot be created or destroyed, only transferred between different stores.

Energy can be transferred by: H[blank_start]eating[blank_end] M[blank_start]echanical Work[blank_end] W[blank_start]aves[blank_end] E[blank_start]lectrical Work[blank_end]

The work done by a force is equal to...

Electrical work is [blank_start]work done[blank_end] when [blank_start]a current flows.[blank_end] Electrical work = [blank_start]voltage[blank_end] x current x [blank_start]time[blank_end] Electrical energy [blank_start]transferred[blank_end] = [blank_start]charge[blank_end] x potential difference

Power is...

When energy is [blank_start]transferred[blank_end], some energy is [blank_start]wasted[blank_end]. This [blank_start]dissipates[blank_end] to the environment. For example, [blank_start]friction[blank_end] leads to the transfer of energy into a thermal store. This heat then dissipates.

Efficiency = [blank_start]useful power output[blank_end]/[blank_start]total power input[blank_end] x [blank_start]100[blank_end]

Unwanted energy transfers can be reduced by: [blank_start]Lubrication[blank_end] Thermal [blank_start]Insulation[blank_end] Walls in homes

An energy resource is used to [blank_start]generate electricity[blank_end] and other useful forms of energy. Energy resource rotates a [blank_start]turbine[blank_end] -> This rotates a [blank_start]coil of wire[blank_end] in a magnetic field (a [blank_start]generator[blank_end]) -> This produces an electric current: an energy [blank_start]carrier[blank_end].

Fossil Fuels are burnt to heat a fluid, producing [blank_start]steam[blank_end] and turning a turbine. In volcanic places, magma has lots of [blank_start]internal[blank_end] energy. The magma heats [blank_start]rocks[blank_end], which heats water in pipes. This rotates a turbine and is known as [blank_start]geothermal[blank_end] energy. Holding water above the ground is a store of [blank_start]gravitational[blank_end] potential energy. Allowing it to fall rotates a turbine. This is known as [blank_start]hydroelectric[blank_end] power. Waves and tides are stores of [blank_start]kinetic[blank_end] energy. They can rotate turbines.

In a nuclear reactor, the energy stored in the [blank_start]nuclei[blank_end] of atoms is released as [blank_start]kinetic[blank_end] energy. Some of this heats up [blank_start]graphite[blank_end] which then heats up a fluid. This creates steam and rotates a turbine. Solar Cells absorb the [blank_start]electromagnetic[blank_end] waves from the [blank_start]Sun[blank_end]. Some create an [blank_start]electric[blank_end] current without a generator, while some use the heat from the Sun to boil water, create [blank_start]steam[blank_end] and rotate a turbine.

The Sun is the original source of energy for: F[blank_start]ossil[blank_end] fuels S[blank_start]olar[blank_end] Power W[blank_start]ave[blank_end] Energy Wind [blank_start]Power[blank_end] H[blank_start]ydroelectricity[blank_end]

Electricity use [blank_start]increased[blank_end] in the UK through the [blank_start]20th[blank_end] Century as population [blank_start]increased[blank_end]. Electricity use has [blank_start]decreased[blank_end] in the [blank_start]21st[blank_end] Century as appliances have become more [blank_start]efficient[blank_end].

The UK government planned to draw [blank_start]15[blank_end]% of energy from renewable resources by 2020 due to [blank_start]public pressure[blank_end]. The problems with renewable resources are It costs [blank_start]more[blank_end] It is less [blank_start]reliable[blank_end] [blank_start]Politics[blank_end] can interfere