As the hydraulic cylinder rotates around O, the exposed length l of the piston rod P is...

As the hydraulic cylinder rotates around O, the exposed length l of the piston rod P is controlled by the action of oil pressure in the cylinder. If the cylinder rotates at the constant rate and l is decreasing at the constant rate of 150 mm/s, calculate the magnitudes of the velocity v and acceleration a of end B when l = 125 mm.