1. The problem statement, all variables and given/known data Three identical wires Lo, diameter d, are arranged like a Y letter (please see attachment) Each end of the wires is secured to a wall. Initial tension is approximately zero. If the wires are cooled ΔT, find the distance the knot moves to the right and the final tension in each wire. (assume θ does not change when the knot moves.) 2. Relevant equations ΔL = Lo[itex]\alpha[/itex]ΔT ΔL/Lo = -F/AY = [itex]\alpha[/itex]ΔT 3. The attempt at a solution Tensions in wires: Fwire1 = 2 * Fwire2 * cos(θ/2) Here is where I'm stuck. I think that the total expansion is zero, so the equation is something like this ΔLtotal = ΔLwire1 + ΔLwire2 cos(θ/2) = (Lo[itex]\alpha[/itex]ΔT - Lo Fwire1/AY) + ( Lo[itex]\alpha[/itex]ΔT - Lo Fwire2/AY) cos(θ/2) = 0 But I got the wrong answers. It is hard for me to visualize how the system changes with the assumption that θ is still the same. It doesn't make sense. Please help me. Thank you very much.