Conservation of energy

change in GPE(J)= mass(kg) x gravitational field strength (N/kg) x change in vertical height (m)

Kinetic energy(J) = 0.5 x mass( kg) x speed2 (m/s2)

(To scale)
1.Useful energy= points to the right
2.Wasteful energy= points down

energy cannot be created or destroyed, it can only be converted from one form to another

Kinetic energy transfers to gravitational potential energy

Kinetic energy transfers to heat energy from friction against the floor

Electric energy transfers to thermal energy and perhaps some light and sound energy

Don't interact and are not influenced by the external environment.

There is no change of energy in that system

When they cause a rise in temperature so dissipating energy in heating the surroundings

Energy that is not usefully transferred. We say that this wasted energy dissipates. Fo example, electric energy in a Tv is transferred to sound and light energy which is useful but also thermal which isn't.

It reduces friction from kinetic energy which causes thermal energy transfer

It creates a barrier from energy from escaping.For example, on a house, the walls are built to be thick to reduce thermal energy from escaping

The ability of an object to transfer heat

The rate of energy transfer is reduced when the wall is thicker so less energy escapes, keeping the building warm

House are made from materials that are poor conductors to prevent thermal energy from leaving

Useful energy output / total energy input

Mechanical devices can be made more efficient through lubrication to reduce the friction between moving parts of a machine and increase the amount of useful energy transferred.

Energy that can never be replaced once it is completely used up

energy made from a naturally replenishable source that won't run out

oil, coal, natural gas

Wind power, bio-fuel, hydro-electricity, tidal power, solar power

Adv- Don't depend on weather, cheap to produce, good supply at the moment
Disadv- Produce green house gases, non-renewable

Adv- can be small and portable, no pollution, can be used remotely
Disadv- Expensive, depends on light intensity

Adv- no pollution, running costs are low
Disadv- noisy, looks bad, depends on wind, high set up costs

Adv- No pollution
Disadv- tides aren't strong enough in the Uk, not very useful, large areas get flooded

Adv- No CO2 emissons
Disadv- Smells bad, needs complete combustion

Adv-no pollution, low running costs
Disadv- cost of drilling is expensive, limited amount of places

Adv- no pollution, no fuel costs, will never run out
Disadv- very expensive, need large areas of land

energy from the sun that is converted into thermal or electrical energy

The use of a windmill to drive an electric generator

As the tide comes in, water rushes in and turbines spin the other way

energy produced by burning organic matter, such as wood, food scraps, and alcohol

energy from hot rocks underground

using the power of moving water like tides and dams to produce electricity