Would this be right to say Fc is out of the circle?
I have a question for my engineering assignment, its pretty simple in fact. I just have one small problem..
Here is what I have. There is a spring attached to a stationary point, and a roller that travels down a parabolic curve. This shouldn't matter too much though, you will understand just from the forces.
I'm not sure if Fc should be +ve (into the circle) or ve (out of the circle).
Forces upwards (+ve):
 Tension from pulling spring
Forces downards (ve):
 Weight = mg
I need to find the normal (N) of the circle on the slider.
So would it be true to say Fc pushes downwards (out of the circle) and thus is ve? I don't see how Fc can push into the circle and be +ve. I think about it this way, say I have a piece of string with a rock attached, and swing it in a circular motion. The rock always pulls the string tight and stays to the edge of the circle, considering there is enough speed. So Fc = T, T is into the centre of the circle and Fc pushes out of the circle.
Any explanations or help would be great, if you need a picture of the assignment let me know, but hopefully I've explained it well enough.
