M(r) = mass of gas in a sphere of radius r.Can any particle, Fg=Fcpr2GM(r)m=rmv2
GM(r)m=2(K)r⇒M(r)=GM2KrOn differentiating w.r.t r, drdM=Gm2K.................(1)Here dM = mass of gas in a spherical shell of radius r and thickness dr∴dM[ρ(r)](dv)=[ρ(r)]4πr2dr....(2)Substitute (2) in (1)dr[ρ(r)]4πr2dr=Gm2K∴ρ(r)=2πr2GmKn(r)=mρ(r)=2πr2Gm2K