I have a counterweight system I am trying to develop. One of my associates and I are in disagreement over something though. The system is simple, it is effectivly two 850 Lb weights connected together by a chain. The chain is suspended by two pulleys. One of the pulleys is connected to motor. I am trying to calculate the torque required to move the system 40 inches in 1 second. I believe the only forces that I have to overcome is inertia due to acceleration and the system friction. Assuming there is no friction the inertia is all that is l have to overcome. Here is my question: Is the inertia load 1700 Lbs or 850. My associate says gravity will remove one of the loads but if gravity acts on both weights shouldnt it cancel out?