Given that the string remains taut, show that the speed of C immediately after the collision is sqrt(ga).
I can solve this, but I'm not really content with my reasoning. I did it in two ways, once considering energy and once using the standard equations of motion, but I think I'm doing something wrong... So I wanted to see how you guys would approach it.
Yup. It's from the 2nd review exercise.
When C joins B: