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3 marksConservation of Energy

CAPE Physics Unit 1 · 2007 · Paper 2 · Question 5(b)(iii)

On a construction site, a winch lifts a paint-filled drum weighing 1200 N through a height of 35 m in 24 s.

The winch has an efficiency of 70%. How much electrical power is required by the winch's motor?

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Other parts of this question

  1. 5(a)(i)A body of mass m is accelerated from rest to a speed v by the application of a constant force. Derive the equation E_k = (1/2)mv² for the kinetic energy of the…[3 marks]
  2. 5(a)(ii)A satellite is launched from the ground and placed in an orbit with a height of 900 km. Why does the equation ΔE_p = mgh NOT apply to this situation?[1 mark]
  3. 5(a)(iii)The car on a roller coaster (Figure 6) is travelling at 12 m s⁻¹ at the top of a hill but a short time later when it reaches the bottom of the hill, 35 m…[5 marks]
  4. 5(b)(i)What was the gain in potential energy of the load?[1 mark]
  5. 5(b)(ii)Find the power output of the winch motor.[2 marks]
  6. 5(c)(i)Sketch graphs to show the variation with time of the drum's displacement and velocity.[1 mark]
  7. 5(c)(ii)Find the time taken by the drum to reach the ground.[1 mark]

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