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Center of Mass and Collision question

2022 · Q148
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Center of Mass and Collision question

2022 · Q148

NEETPhysicsCenter of Mass and CollisionMCQ+4 / −1

Given below are two statements : One is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : When a fire cracker (rocket) explodes in mid air, its fragments fly in such a way that they continue moving in the same path, which the fire cracker would have followed, had it not exploded.

Reason (R) : Explosion of cracker (rocket) occurs due to internal force only and no external force acts for this explosion.

In the light of the above statements, choose the most appropriate answer from the option given below

  1. A
    (A) is not correct but (R) is correct
  2. B
    Both (A) and (R) are correct and (R) is the correct explanation of (A)
  3. C
    Both (A) and (R) are correct but (R) is not the correct explanation of (A)
  4. D
    (A) is correct but (R) is not correct
View written solutionFree

Correct answer: A

As per Newton's II law for a system

$${\overrightarrow F _{external}} = {{d\overrightarrow P } \over {dt}} = m{{d{{\overrightarrow v }_{com}}} \over {dt}}$$

As explosion occurs due to internal forces only, the velocity of centre of mass would remain unchanged. This means that the centre of mass would continue to travel along same path as it was moving before explosion.

The fragments can however move individually along various directions.

Thus (A) is not correct and (R) is correct.

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