From mechanics of materials it is known that when a static load P is applied at the end B...

From mechanics of materials it is known that when a static load P is applied at the end B of a uniform metal rod fixed at end A, the length of the rod will increase by an amount δ = PL/AE,where Lis the length of the undeformed rod, Ais its cross-sectional area, and Eis the modulus of elasticity of the metal. Knowing that L =450 mm and E = 200 GPa and that the diameter of the rod is 8 mm. and neglecting the mass of the rod. determine (a) the equivalent spring constant of the rod. (b) the frequency of the vertical vibrations of a block of mass m= 8 kg attached to end B of the same rod.