1. Energy Revision Define renewable energy.
Provide 2 reasons in which fossil fuels are bad for the environment.
What is the energy transfer of a ball falling from the cliff?
Which renewable energy does the diagram describe?
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What is the energy transfer of this renewable energy?
Which renewable energy does the diagram describe?
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What is the energy transfer of this renewable energy?

2. Sankey Diagrams
A lot of energy is wasted as heat energy in a light bulb. For every 50 J of electrical energy applied to the light bulb, only 10 J are transferred to light energy.
Draw an energy transfer diagram (Sankey diagram)
1cm = 10J
A lot of energy is wasted as heat energy in a television. For every 80 J of electrical energy applied to the television, only 40 J are transferred to light energy.
Draw an energy transfer diagram (Sankey diagram)
1cm = 10J
Calculate the efficiency of the light bulb.
Calculate the efficiency of the television.

3. Potential Energy and Kinetic Energy Revision
Define potential energy.
Define kinetic energy.
Work = Force x Distance
 Potential energy = Mass x Gravity x Height
 Kinetic energy = ½ x Mass x Speed2
 Power = Work / Time
 Gravity = 10 m/s2 or 10 N/kg
Bob is holding a basketball above a cliff that is 100 m high. The bowling ball weighs 8 kg.
(a) What is the potential energy of the ball at the top of the cliff?
(b) What is the potential energy of the ball at the base?
(c) Calculate the velocity with which the ball hits the ground.