Dievsky V.A - Solution of problem D7 variant 14 task 2

D7-14 (Task 2) Dievsky

The mechanical system is supplied with a weightless viscous dampener, which is installed at point B parallel to the axis of the elastic element, and creates a resistance force proportional to the speed of point B: R = -bvB, where b = 20 Ns / m is the coefficient of resistance. In addition, the force acting on the system is F = F0 sin pt, where F0 = 60 N, p = 25 s-1 is the amplitude and frequency of the driving force. The driving force is applied at point B and acts parallel to the axis of the elastic element. (If point B coincides with point A, the scheme indicates B = A). It is required to determine the amplitude of the purely forced oscillations of the system.