## Energy, work, and power

Energy

Energy is always conserved. It is never created or destroyed. Rather, energy is transferred or transformed from one form to another. The main types of energies that you need to know are listed below.

Conservation of Energy

As mentioned above, energy is never created or destroyed – it is only transferred or transformed from one form to another. Here are some common simple examples:

• In a light bulb, electrical energy is transformed into heat energy and light energy
• In a water fall, gravitational energy is transformed into kinetic energy
• In a battery, chemical energy is transformed into electrical energy

The higher an object is from the earth, the greater it’s gravitational potential energy. In the waterfall example above, as the water falls from a higher area to a lower area, the gravitational energy decreases while the kinetic energy increases via the transformation of energy.

Kinetic Energy & Gravitation Potential Energy

Kinetic energy – The kinetic energy of a moving object can be calculated by the formula below:
KE = 0.5 x mv2

Gravitational potential energy – The gravitational potential energy of an object above ground level can be calculated by the formula below:
GPE =mgΔh
[m = Mass(kg), g = Gravitational Force (10 m/s2), Δh = Change in Height(m)

Energy Resources

Energy resources are used to produce electrical energy from other forms of energy

Efficiency

DIAGRAMMATIC REPRESENTATIONS OF ENERGY TRANSFER:

Sankey diagrams are used to show the different forms of energy emitted from a single energy input. For this course you will only need to know how to interpret these diagrams.

This basically shows the input energy and how much of that energy is converted into what in a visual form of arrows that split off. The arrow heads usually add up to the other end of the arrow to represent conservation of energy

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