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JAMB Physics 1987 Question 9

Question 9

Work, Energy and Power

A body rolls down a slope from a height of 100 m. Its velocity at the foot of the slope is 20 m s−1. What percentage of its initial potential energy is converted into kinetic energy? [g = 10 m s−2]

  1. A.40%
  2. B.35%
  3. C.20%
  4. D.15%
Show the answer and explanation

Answer: C (20%)

Explanation

Per kilogram, PE = gh = 1000 J and KE = ½v² = 200 J. 200/1000 = 20%.