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AQA · GCSE · Physics · Higher

Calculating Work Time from Power

Q01.3 3 marks

The power output of the whisk is 92 W.

Calculate the time for the whisk to do 23 000 J of work.

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Marking points

  1. 1 Uses 92 = 23 000/time.
  2. 2 Correctly rearranges to divide 23 000 by 92.
  3. 3 Gives the final time as 250 s.

Full-mark answer

Using P=W/tP = W/t: 92=23 000/t92 = 23\,000/t, so t=23 000/92=250 st = 23\,000/92 = 250\ \text{s}.

Why this answer loses marks

Multiplies the work done by the power.

After making time the subject, divide the work done by the power.

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