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1.2 Conservation and dissipation of energy

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Question 5

A powered mechanism opens the vents of a greenhouse. The energy transfers during two tests are shown in the table.

TestTotal input energy transfer (J)Useful output energy transfer (J)
Before lubrication50002000
After lubrication50003500
a.

Calculate the increase in the efficiency of the mechanism after lubrication.

[3]
b.

Explain why lubrication increased the efficiency of the mechanism, and why the mechanism is still not 100% efficient.

[3]
Markscheme

1.2 Conservation and dissipation of energy Questions

  1. GCSE
  2. /Physics
  3. /1.2 Conservation and dissipation of energy

104 exam-style questions on AQA GCSE Physics 1.2 Conservation and dissipation of energy, covering 1.2.1 Energy transfers in a system and 1.2.2 Efficiency. Each one has a worked solution and a mark scheme showing where the marks go.

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