Physics Two Dimensional Motion Question 281

Question: A particle moves in a circular orbit under the action of a central attractive force inversely proportional to the distance $ ‘r’ $ . The speed of the particle is

[CBSE PMT 1995]

Options:

A) Proportional to $ r^{2} $ B) Independent of $ r $ C) Proportional to $ r $ D) Proportional to $ 1/r $

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Answer:

Correct Answer: B

Solution:

$ \frac{mv^{2}}{r}\propto \frac{K}{r}\Rightarrow \upsilon \propto r{}^\circ $ i.e. speed of the particle is independent of r.