Move sphere around a cube using conventional physics

So my objective is to use physics manually (code it) instead of using Unity’s physics or any other thing that comes with Unity to make a sphere rotate around a cube (Eg: RotateAround).
For the sphere, the user inputs it’s speed (angular) and distance from sun. The cube acts as the origin and if the user moves the cube, the sphere must move with it.
The problem I’m having is not with the physics as that is pretty straightforward. But, when I try to apply the physics in a C# script for Unity is when everything goes haywire.
I was wondering if anybody could help me with applying the physics in C# for the GameObjects.

I found the answer in case you also have the question:.