Forces and Energy

Chemical Energy::

Energy stored in chemical bonds of substances like food,fuel

Gravitational Potential Energy:

Energy an object possessed due to its position relative to a a refrence point usually the earth

Elastic Strain Energy

Energy stored in an object when its compressed, streched or deformed

Kinetic Energy

Energy possessed by a moving object

Elerctostatic energy

energy stored in charged objects due to their seperation in an electric field

Nucleur Energy

Energy stores in the nucleus of an atom

(Internal) Thermal Energy

Total energy stored in the microscopic motions anf interactions of particles within a substance

Mechanical Working:

Transfer of energy by the action of a force like lifting a weight

Electrical Working

Transfer of energy by an electric current, such as in batteries or eletric motors

Waves( electromagnetic and sound)

Transfer of energy through waves like light and sound waves

heating

Transfer of energy through thermal proccess like heating water in a boiler

Kinetic Energy formula

Kinetic Energy= ½ x m x v²

Change in Gravitational Potential Energy:

Gravitaional potentail= mass x gravity x change in height

Sankey Diagram

show energy transfer- that energy cannot be lsto or destyoed

• he straight arrow pointing to the right represents the energy that ends up in the desired store; this is the useful energy output

• The arrows that bend away represent the wasted energy

Main source of all energy

Radiation from the Sun is the main source of energy for all our energy resources except geothermal, nuclear and tidal

Fossil fuels (chemical energy)

- Fossil fuels are burned in a boiler

• Chemical energy → thermal energy (heat)

• Water is heated to produce steam

• Steam turns a turbine

• Turbine drives a generator

• Generator produces electrical energy

• Advantages:

• Reliability: They offer consistent and high-power output on demand, unlike intermittent sources like wind or solar.

• Disadvantages:

• Greenhouse Gas Emissions: Burning fossil fuels releases , contributing significantly to global warming and climate change,

Biofuels (chemical energy)

- Biofuels are burned like fossil fuels

• Chemical energy → heat

• Heat produces steam

• Steam turns a turbine → generator

• Electrical energy is produced

• Same process as fossil fuels, just different fuel source

• Advantages: Renewable:

• Can be replenished relatively quickly by growing new plants, unlike finite fossil fuels.

• Disadvantages:

• Small scale

Hydroelectric (dam)

• Water stored at height → gravitational potential energy

• Water flows down → kinetic energy

• Turns turbine

• Turbine drives generator

• Advantages:

• Renewable

• Disadvantages:

• Reliability Depends on rainfall

Tides

• Movement of water due to tides

• Water flows through turbines

• Drives generator

• Generator produces electrical energy

• Advantages:

• Renewable

• Disadvantages:

• Reliability Depends on tides

Waves

• Wave motion moves devices (e.g. floats)

• Motion used to turn turbines

• Drives generator

• Generator produces electrical energy

• Advantages:

• It is a renewable energy resource, meaning it will not run out.

• It produces no greenhouse gases (like $CO_{2}$) during operation.

• Disadvantages:

• Not reliable- relies on wave pattern

Geothermal energy

1. Heat from inside the Earth heats water

2. Produces steam

3. Steam turns turbine

4. Turbine drives generator

5. Generator produces electrical energy

• Advantages:

• No pollution

• Disadvantages:

• Only possible in geothermal areas

Nuclear fuel

• Nuclear reactions release thermal energy

• Heat used to produce steam

• Steam turns turbine

• Turbine drives generator

• Generator produces electrical energy

• Advantages:

Efficient source of electricity

• Disadvantages:

• Very expensive to build and to run

Solar cells

• Light energy from Sun falls on solar cells

• Light energy → electrical energy directly

• No turbine or generator needed

• Advantages:

• Clean and Cheap

• Disadvantages:

• Not reliable- Needs good weather

• Needs big area

Wind

• Sun heats Earth unevenly → causes air movement (wind)

• Wind turns turbine

• Turbine drives generator

• Generator produces electrical energy

• Advantages:

• Clean

• Cheap to run

• Disadvantages:

• Not reliable- Needs wind

• Expensive build cost

Solar panels (heating water)

• Infrared radiation from Sun heats water directly

• creating steam

• turning turbine

• Turbine drives a generator

• Generator produces electrical energy

• Advantages:

• Renewable Energy: Uses sunlight to directly heat water, making it sustainable and non-polluting.

• Disadvantages:

• Reliability- needs the sun

Sun energy

Energy is released by nuclear fusion in the Sun

Nucleur Fusion

Research is being carried out to investigate how energy released by nuclear fusion can be used to produce electrical energy on a large scale

Efficiency of energy transfers and power

Recall and use the equation:

efficiency = useful energy output/Total energy output × 100%

or

efficiency = power input useful/ total power output ×100%

Work Formula

Work = force x distance moved in the direction of the force

work is in joules

• Same as energy transferred

force is in newtons

Work

mechanical or electrical work done is equal to the energy transferred( same thing) eg: 2400j of work done = 2400j gravitation potential

work is only done if there is movemnt against an oppsoing force

Power Definition

The rate at which works is done or

The rate at which energy is change from one form to another

Power Formula

P= (delta)E/t or P = W/t

Power= change in energy/time

Power = work done / time take or

Power = energy transferred/time

units: watts (W) / or 1 joule/second

Delta Notation:

Delta: Meaning a Change in

Prefix

• kilowatt (kW) = 10310^3103 W = 1,000 W

• megawatt (MW) = 10610^6106 W = 1,000,000 W