The system below is used to raise heavy objects, via a hydraulic cylinder AB, and a roller at D. The roller at D is in contact with the ground and connected to member DCB via a frictionless pin. Member DCB has a right angle at C. Connections O, A, B and C are also frictionless pins. The weights of all members can be neglected. If the system is subjected to a 1500 lb load as shown in the figure below: a) Identify the 2-force member(s) b) Find the reaction(s) at D c) Find the reaction in the piston AB 28" 1500 lb 12" 60 15"