IIT JEE 2008 P1 Q29

2 Answers

for >R
F âˆž 1/r² .. mv²/r âˆž 1/r²
v² âˆž 1/r .. . v âˆž 1/âˆšr

F âˆž r .. mv²/r âˆž r
v² âˆž r² .. . v âˆž r

so C

The answer is C

Force of grav increases until r=R

and then decreases.

So, v increases until R and then gradually decreases till infinity

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