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Gravitation

Question
CBSEENPH11020366

The height at which the acceleration due to gravity becomes g/9 (where g = the acceleration due to gravity on the surface of the earth) in terms of R, the radius of the earth, is

  • 2R

  • fraction numerator straight R over denominator square root of 2 end fraction
  • R/2

  • square root of 2 straight R end root

Solution

A.

2R

fraction numerator GM over denominator 9 straight R squared end fraction space equals space fraction numerator GM over denominator left parenthesis straight R plus straight h right parenthesis squared end fraction
rightwards double arrow space 3 straight R space equals space straight R plus straight h
rightwards double arrow space straight h equals space 2 straight R