I made notes on this in class, but I did not understand everything about it. So, what I know is that vertical motion is when the object goes around in a circle like this: And horizontal I guess it is like this: But then I am very confused regarding what my teacher told me for horizontal motion. She told me there is the top and the bottom for horizontal motion which I completely do not get because it is always at the same distance to the ground, and so the tension is perpendicular to mg but the force diagram she given the class is just not like that. The 'experiment' was called ''rotating rubber on a string (horizontal) - assuming the string is horizontal''. For the 'top' (I still don't know how top and bottom exists here) it is mg + T = Fc and for bottom T - mg = Fc. Could someone please explain if I am misunderstanding what she means by horizontal motion or explain how top and bottom exist?