3. A quarter-elliptic or cantilever leaf spring of length 1 with n plates each of breadth b and thickness t is so shaped that circular bending occurs. Derive expressions: (a) for the maximum stress due to bending and (b) for the maximum deflection due to an end load W. If the maximum allowable bending stress is 400MN/m2 and the spring has 5 plates each 70mm wide by 10mm thick with the length of the longest plate 0.4m, find: (c) the maximum value for the load W, and (d) the deflection at the end. Assuming that the spring just straightens under these conditions, determin initial radius of curvature of the plates. For steel E=200GN/m2