1. The problem statement, all variables and given/known data in this problem , it's not clear that whether the shortening of 1.5mm is for which rod , there are 3 rods in the diagram and forces applied at which part to cause the rotation ... .... 2. Relevant equations 3. The attempt at a solution Can somenoe explain about it ? if the forces is applied at rod Ef , then rod EF will shorten , and both rod AB and rod CD will either undergo shortening and lengthening , right ?