A steel shelf is used to support a motor at the middle. The shelf is 1 m long, 0.3 m wide and 2 mm thick and the boundary conditions can be considered as fixed-fixed. Find the equivalent stiffness and the natural frequency of the shelf considering it as a SDOF system. Assume that the mass of the motor is 10 kg and operating speed is 1800 rpm. Given, Mass, m = 10 kg Length, L = 1 m Rotating speed, N = 1800 rpm Modulus's Young, E = 200 GPa