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NDA 2020 GAT · General Knowledge · Motion, Forces and Gravitation · easy

A rocket moves forward by expelling hot gases backward at high speed. This is an application of

Single correct option

A rocket moves forward by expelling hot gases backward at high speed. This is an application of
  1. A. Newton's third law of motion
  2. B. Newton's first law of motion
  3. C. Bernoulli's principle
  4. D. Archimedes' principle
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Answer: (A) Newton's third law of motion

The rocket pushes the gas backward (action) and the gas pushes the rocket forward with an equal and opposite force (reaction). It needs no air to push against, so it works in vacuum. Bernoulli and Archimedes concern fluids in motion and buoyancy, which do not explain the thrust.
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Original question written in the NDA 2020 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