SAT2 关于引力地一道题 给一下关于万有引力的所有公式 THX

SAT2 关于引力地一道题 给一下关于万有引力的所有公式 THX
The moon has mass Msand radius R.A small object is dropped from a distance of 3R from the moon's center.The object's impact speed when it strikes the surface of the moon is equal to genghaoxia KGM/R for k=
A 1/3 B 2/3 C 3/4 D 4/3