The 60kg collar slides on the curved rod in the vertical plane with negligable friction under the action of constant force F in the cord guided by the small pulley at D. If the collar is released from rest at A, determine the force F which will result in the collar striking the stop at B with a velocity of 4m/s. Point A is located 0.6 m horizontally away from point B and 0.2 m below the pulleys at D. Point B is located 0.2 m above and to the left the pulleys at D.

I know that I have to put this into cylindrical coordinates but I have no idea where to start or how to do that. Does anyone have any idea?