A 5 kg body falls 20 m from rest against a constant air resistance of 9 N. Its speed on reaching the ground is (g = 9.8):

  1. 8.94 m/s
  2. 35.8 m/s
  3. 17.9 m/s
  4. 19.8 m/s
Answer

C) 17.9 m/s

mgh - fh = 12mv^2 Rightarrow 980 - 180 = 800 J; v = 17.9 m/s. SLO P-11-B-32 · Application

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