Kinetic and Potential Energy

• Energy is stored in thermal, kinetic, gravitational potential, elastic potential, chemical, magnetic, electrostatic, and nuclear forms.
• A system is defined as an object or a group of objects.
• A closed system experiences no net transfer of energy into or out of it.

Energy Transfer

• Energy is transferred through heating, such as a kettle heating water.
• Mechanical Work, like moving objects, transfers energy.
• Electrical work, for example circuits, can transfer energy.
• Radiation, including light and sound waves, allows for energy transfer.

Kinetic Energy

• Kinetic energy is calculated as KE = (1/2)mv^2
• 'm' represents mass in kilograms (kg).
• 'v' represents velocity in meters per second (m/s).
• Kinetic energy increases with greater mass or speed.

Gravitational Potential Energy

• Gravitational potential energy (GPE) is calculated as GPE = mgh
• 'm' is mass in kilograms (kg).
• 'g' is gravitational field strength in Newtons per kilogram (N/kg)
• 'h' is height in meters (m).
• Earth's gravitational field strength is approximately 9.8 N/kg.

Kinetic / Gravitational Potential Energy Transfer

• When objects fall, gravitational potential energy converts into kinetic energy.
• When objects are thrown upwards, kinetic energy converts into gravitational potential energy.
• Total energy is conserved in the absence of air resistance.

Specific Heat Capacity

• Specific heat capacity is the energy needed to raise the temperature of 1kg of a substance by 1°C.
• The formula to calculate it is: ΔE = mcΔθ
• ΔE represents the change in energy measured in joules (J).
• 'm' is mass in kilograms (kg).
• 'c' is specific heat capacity in joules per kilogram per degree Celsius (J/kg°C).
• Δθ is the change in temperature in degrees Celsius (°C).
• Heating blocks of different materials is a practical application.

Conservation of Energy

• Energy cannot be created or destroyed, only transferred from one form to another.
• In closed systems, the total energy remains constant.

Conduction, Convection, and Radiation

• Conduction: the transfer of heat in solids by vibrating particles.
• Convection: the transfer of heat in fluids (liquids or gases) through the movement of warmer, less dense regions.
• Radiation: the transfer of heat by infrared waves, which can travel through a vacuum.

Reducing Unwanted Energy Transfers

• Insulation reduces heat loss through methods such as double glazing, loft insulation, and cavity walls.
• Lubrication reduces friction.

Power and Work

• Work done is calculated as W = Fd
• 'W' is work done in joules (J)
• 'F' is force in newtons (N)
• 'd' is distance in meters (m).
• Power is calculated as P = E/t = W/t
• 'P' is power in watts (W)
• 'E' is energy transferred in joules (J)
• 't' is time in seconds (s).

Efficiency

• Efficiency = (Useful energy output / Total energy input) x 100
• Efficiency can be improved by reducing wasted energy through insulation and lubrication.

Energy Resources

• Energy resources are divided into renewable and non-renewable types.
• Renewable resources will not run out, examples include solar and wind power.
• Non-renewable resources have a finite supply, examples include fossil fuels.

Fossil Fuels and Nuclear Energy

• Fossil fuels include coal, oil, and gas.
• Fossil fuels are reliable and have a high energy output.
• Fossil fuels produce CO₂ which contributes to climate change, and SO₂ which contributes to acid rain.
• Nuclear power uses materials like uranium and plutonium.
• Nuclear power produces no CO₂ and has a high energy output.
• Nuclear power produces radioactive waste and is expensive.

Wind and Solar

• Wind power uses turbines to convert wind energy into electricity.
• Wind power produces no pollution and are renewable.
• Wind power is unreliable and wind-dependent and can be noisy.
• Solar power involves solar panels absorbing sunlight to create electricity.
• Solar power has no running costs and is renewable.
• Solar power is unreliable at night and has expensive installation costs.

Geothermal

• Geothermal power utilizes heat from underground, especially in volcanic areas.
• Geothermal power is reliable and emits no CO₂.
• Geothermal power only works in specific locations.

Biofuels

• Biofuels are made from organic material, such as crops and manure.
• Biofuels are renewable and carbon neutral.
• Biofuels uses land and can increase food prices.

Hydroelectricity and Tidal Barrages

• Hydroelectricity uses dams to store water, which is then released to turn turbines.
• Hydroelectricity is reliable and produces no pollution.
• Hydroelectricity floods land and affects wildlife.
• Tidal barrages use tide movement to generate electricity.
• Tidal barrages are predictable and renewable.
• Tidal barrages are expensive and affects marine life.