Hey, I have this question here, the hardest one on this sheet, and I've been stuck on it all day now. I'd really appreciate maybe just a hint, as I want to do it myself but I just need a kickstart. I drew three free body diagrams for each position of the pendulum, then marked off tension and the force of gravity. I ended up with three equations but it never went anywhere and I truly am stuck on this. Any hints would be appreciated. Thanks.