A lifting system receives 1200 J per operation. Its motor transfers 75% of this energy to the lifting mechanism. The mechanism dissipates 300 J and transfers the rest usefully.
A new mechanism dissipates 120 J per operation. The motor and its input energy are unchanged.
What is the new overall efficiency of the lifting system?
50%50\%50%
75%75\%75%
65%65\%65%
87%87\%87%
100 exam-style questions on Edexcel GCSE Physics 3.2 Dissipation and efficiency, covering 3.2.1 Dissipation of energy, 3.2.2 Reducing unwanted energy transfers, 3.2.3 Efficiency, and 3.2.4 Increasing efficiency. Each one has a worked solution and a mark scheme showing where the marks go.