1. The problem statement, all variables and given/known data In a pole with dimension lo=5m and section S=20 cm square acts the force of F=20Kn vertically downwards . How long will it go downwards, ---- thus delta l is needed 2. Relevant equations I have delta l /lo =1/ EY *F/S 3. The attempt at a solution I know the solution is giving me only delta l = 0.25 mm how do i get delta l from above formula and what about EY which isnt needed ? Could this be correct delta l = lo/ey * F/s ?