Which forces affect the ball in A, B, C and D?

1. The problem statement, all variables and given/known data



I have attached a picture. I just want to know which forces affect the ball at different times: A, B, C and D. Could someone please sum it up really fast? : -)







2. Relevant equations







3. The attempt at a solution

Attached Images

Skærmbillede 2014-04-30 kl. 13.20.59.png (18.0 KB)