me zero theta (0) = pi/2, find theta (t) and y (t)

the mass of the piston is 2kg. rod BD has a mass of 1.5 kg and l=250 mm. Rod AB has a mass of 2kg, b=100mm and has a constant angular velocity of 10 rads/s.knowing that rod AB is rotating at a constant angular velocity (dtheta/dt = 10 rads/s) and given that at time zero theta (0) = pi/2, find theta (t) and y (t)