GM/R\sqrt{\mathrm{GM} / \mathrm{R}}GM/R
GM/2R\sqrt{G M / 2 R}GM/2R
2GM/R\sqrt{2 \mathrm{GM} / \mathrm{R}}2GM/R
GM/R2\sqrt{\mathrm{GM} / \mathrm{R}^{2}}GM/R2