Two particle of mass m and M are initially at rest at inifinte distance . Find their relative velocity of approch due to grvitational atraction when d is their separation at any instant . [Hint : From the principle of conservation of energy `(GmM)/(d) =(1)/(2)mv_(1)^(2) +(1)/(2)v_(2)^(2).` . From the principle of conservationl of momentum , `mv_(1)-Mv_(2)=0` . Relative velocity of approch =` V_(1)+V_(2)`]

Answer

`sqrt(2G(m+M)//d)`