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JAMB Physics 1983 Question 17

Question 17

Work, Energy and Power

A man of mass 50 kg ascends a flight of stairs 5 m high in 5 seconds. If acceleration due to gravity is 10 m s−2, the power expended is

  1. A.100 W
  2. B.200 W
  3. C.250 W
  4. D.400 W
  5. E.500 W
Show the answer and explanation

Answer: E (500 W)

Explanation

Work = mgh = 50 × 10 × 5 = 2500 J. Power = 2500 ÷ 5 = 500 W.