Work, Power and Energy

• Work is calculated by multiplying force (N) by distance (m).
• The unit for work is Joules (J).
• Power is calculated by dividing work done (J) by time taken (s).
• The unit for power is Watts (W).
• Convert kg to Newtons (N) and cm/mm to meters when solving work problems.
• Convert minutes to seconds when solving power problems.
• Energy is the ability to do work and is measured in Joules (J).

Types of energy include

• Kinetic energy, for example waves
• Potential energy, such as in a spring
• Sound energy, for instance guitar strings
• Heat energy, like that measured by a thermometer
• Chemical energy, like that in batteries
• Electrical energy, such as from an electric car
• Magnetic energy, for example magnetic trains
• Solar energy, like that from a Crook's radiometer
• Nuclear energy, such as from a nuclear power station

Principal Conservation of Energy

• Energy is neither created nor destroyed, but is converted between forms.

Energy Conversions

• Chemical energy in phones converts to electrical and then sound energy
• Chemical energy in food converts to kinetic energy when the body moves
• In nuclear power stations, nuclear energy converts to electrical
• In a light bulb electrical energy converts to light and heat
• In MP3 players, electrical energy converts to sound
• In food mixers, electrical energy converts to kinetic energy

Ways of conserving energy

• Insulate homes to prevent heat loss
• Switch off electrical devices when not in use
• Use energy-saving bulbs
• Use public transport instead of driving

Non-renewable energy sources include

• Oil
• Turf
• Coal
• Gas
• These sources deplete and come from dead things

Advantages and Disadvantages of Non-Renewable Energy

• Easy and cheap to obtain but cause greenhouse gases, pollute atmosphere, and cause acid rain

Renewable energy sources include

• Solar: derived from the sun
• Hydroelectricity: derived from the waves in water
• Wind
• Tidal
• Nuclear
• Geothermal
• Biomass

Source of energy: Solar

• Solar energy advantages consist of being free and does not pollute the atmosphere
• The disadvantages consist of being expensive to install and also only a small % is actually converted

Source of energy: Hydroelectricity

• Advantages consist of being cost efficient and also does not pollute the atmosphere
• Disadvantages consist of dams risking valley flooding and destroying habitats

Source of energy: Wind

• Advantages consist of being free and does not pollute the atmosphere
• Disadvantages consist of no electricity being produced on calm days while being noisy and spoiling the countryside

The Sun

• Primary source of energy.
• Plants trap sunlight via photosynthesis.
• Heat from the sun keeps us warm.
• Winds and waves can be used to produce electricity
• Solar cells and panels convert heat energy to electrical energy.

Nuclear Fission

• Large nucleus divides into two equal parts, but radio active substances are released
• Radiation is harmful and can kill cells and induce cancer.
• Nuclear fission is non-renewable because uranium run out.

Nuclear Fusion

• Light nuclei join together.
• Nuclear fusion is renewable.

Learn about work, power, and energy, including calculations and units. Explore different types of energy such as kinetic, potential, sound, heat, chemical, electrical, magnetic, solar, and nuclear energy. Understand the principal of conservation of energy.