T=L/V, L=2πR =>T=2πR/V, F=GmM/R², F=ma => a=GM/R², a=V²/R =>V=√GM/R => R↑=> V↓, T=2πR·√R/√GM=2π√R³/√GM, R↑=> T↑.
T=L/V, L=2πR =>T=2πR/V, F=GmM/R², F=ma => a=GM/R², a=V²/R =>V=√GM/R => R↑=> V↓, T=2πR·√R/√GM=2π√R³/√GM, R↑=> T↑.