1) A pumping unit is used to recover oil. When the walking beam ABC is horizontal, the force acting in the wireline at the well head is 250 lb. The horse-head C weighs 60 lb and has a center of gravity at Gc. The walking beam ABC has a weight of 130 lb and a center of gravity at GB, and the counterweight has a weight of 200 lb and a center of gravity at GW . The pitman, AD, is pin connected at its end and has negligible weight (a two-force member). Determine the torque M which must be exerted by the motor in order to overcome the force at the well head through the following steps.