A semi-elliptical laminated spring, 900 mm long and 55 mm wide, is held together at the center by a band 50 mm wide. If the thickness of each leaf is 5 mm, find the number of leaves required to carry a load of 4500 N. Assume a maximum working stress of 490 MPa. If two of these leaves extend the full length of the spring, find the deflection of the spring. The Young's modulus for the spring material may be taken as 210 GPa. [Ans. 9: 71.8 mm]