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8 Energy – forces doing work

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Question 6

An electric motor winds up the driving weight of a tower clock. The motor has a mean input power of 200 W and an efficiency of 0.75. It raises the 30 kg driving weight through a vertical height of 3.0 m at a steady speed.

Gravitational field strength is 10 N/kg.

How long does the motor take to raise the weight?

[1]
A

6.0 s6.0\ \mathrm{s}6.0 s

B

8.0 s8.0\ \mathrm{s}8.0 s

C

4.5 s4.5\ \mathrm{s}4.5 s

D

3.4 s3.4\ \mathrm{s}3.4 s

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8 Energy – forces doing work Questions

  1. GCSE
  2. /Physics
  3. /8 Energy – forces doing work

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