A 60 kg body falls from rest through 5 m and reaches 8 m/s. The work done against air resistance is (g = 9.8):

  1. 2940 J
  2. 510 J
  3. 2040 J
  4. 1020 J
Answer

D) 1020 J

Loss of PE = mgh = 2940 J; gain of KE = 1920 J; work against friction = 1020 J. SLO P-11-B-32 · Application

Physics MCQ · More Work and Energy MCQs · Practise