This has always confused me, and I'd appreciate any help in clearing this up. Let's say you have 2 masses hanging from a rope, one below the other, like the attached diagram. What is the tension in T2? How would you go about finding it? I am under the impression it's the vector sum of the force of gravity and the force of the 10.0kg mass on the 15.0kg mass, but it doesn't seem right to me. Can someone please explain? Thank you very much!