Page 134 - Knowledge Organiser Yr9 24-25

Knowledge Base: Science P1: Energy Year 9
7. Work Done and Power
7.1
What is work done?
A measure of the energy transferred from one store to another.
8. Renewable Energy Resources
8.1
What are the three main uses of energy resources?
Transport, electricity generation and heating.
8.2
What is a renewable energy resource?
An energy resource that can be replenished at the same rate or at a faster rate than
it is being used.
8.3
What are the main renewable energy resources that we use on Earth?
Bio-fuel, wind, hydroelectricity, geothermal, tidal, solar, waves.
8.4
What are the advantages and disadvantages of renewable energy resources?
See the next page.
7.2 What is the unit for work done?
7.5 What is the unit for power?
7.6 What is the unit for time?
Joules (J)
Watts (W) Seconds (s)
7.3
What is power?
The rate at which energy is transferred or the rate at which work is done.
7.4
How is power calculated?
power = energy transferred ÷ time power = work done ÷ time
Worked example questions:
Two electric motors are used to lift a weight to the same height. is now stored in each weight. Motor one does this in 5 seconds. Motor two does this in 10 seconds. Calculate the power of each motor.
Why is motor one more powerful?
5J of energy
9. Non-Renewable Energy Resources
9.1
What is a non-renewable energy resource?
An energy resource that is being used at a faster rate than it can be replenished.
9.2
Name two examples of non- renewable energy resources.
Fossil fuels (coal, oil and natural gas), nuclear fuel.
9.3
What is a fossil fuel?
A fuel formed from the remains of living organisms (plants and animals) millions of years ago.
9.4
What are the advantages and disadvantages of non-renewable energy resources?
See the next page.
A hairdryer has a power of 800W. It is used for 45 seconds. How much energy is transferred in this time?
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