Energy required to move a body of mass 'M' from an orbit of radius 2R

1.	Energy required to move a body of mass 'M' from an orbit of radius 2R to 3R is........
Answer» `(GM)/(12R)` `(GMm)/(3R^(2))` `(GMm)/(8R)` `(GMm)/(6R)` SOLUTION :Change in P.E in displacing a body from `r_(1)and r_(2)` is given by : `DeltaU = GMm [1/(r_(1))-1/(r_(2))]= GMm [1/(2R) -1/(3R)] = (GMm)/(6R)`

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