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NDA 2016 GAT · General Knowledge · Motion, Forces and Gravitation · medium

A body of mass 5 kg moving at 2 m/s is brought to rest in 5 s by a constant retarding force. The magnitude of the force is

Single correct option

A body of mass 5 kg moving at 2 m/s is brought to rest in 5 s by a constant retarding force. The magnitude of the force is
  1. A. 2 N
  2. B. 10 N
  3. C. 0.4 N
  4. D. 25 N
Show answer and solution

Answer: (A) 2 N

Retardation a = (2 − 0)/5 = 0.4 m/s². By Newton's second law F = ma = 5 × 0.4 = 2 N. The value 0.4 N is the acceleration mistaken for the force, 10 N is the product of mass and speed (a momentum-like quantity) and 25 N multiplies mass by time. Always compute acceleration first.
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Original question written in the NDA 2016 GAT pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake