Ball swinging on a string with a peg in its path

[bulldog23]

So is PE at the top zero also?

 

[Dick]

Noooo. PE = m g h. Get some rest and rethink this, ok? It's really not that hard. It's a lot easier than force diagrams.

 

[bulldog23]

alright, thanks for the help

 

[Dick]

No problem. Just remember total energy is constant and = mgh+(1/2)*mv^2. If you know h at any point than you can compute v. Night, night.