1. The problem statement, all variables and given/known data Piano wire weighs 77kN/m^3 and breaks at a stress of 3000MPa. Calculate the length of piano wire that can be lowered down a very deep mine before it breaks. 2. Relevant equations stress = force/area 3. The attempt at a solution Piano wire = 77 000N/m^3 stress = 3000 000 000Pa(N/M^2) Area of cross section = (pi)(d^2)/4 Force exerted by x m^3 of piano wire is (x)(77000) Therefore 3 000 000 000 = (4)(77000)(x) /(pi)(d^2) ASSUME d = 0.0002m x = 0.122399m^3 Volume = (pi)(r)^2 * h 0.122399 = (pi)(0.001)^2 * h h= 38 960 This seems a bit too much. My professor is known for throwing out questions that require "engineering intuition for making assumptions." Not sure if my solution is right or I can do it without making an assumption. This is a problem set, no solutions please but only tell me if I'm way off (or close and where i made the mistake). I appreciate it.