Hi, I'd like to write a program that "simulates" a rigid rod of length L moving in a potential field. The problem is in two dimensions. Friction is assumed to be negligible. The potential field and its gradient is known at every point of the two-dimensional domain. The "mass" of the rod and the magnitude of the potential gradient can be arbitrarily set. The rod has uniform density. I understand that the force acting upon a particle in a potential field is -∇P, where P is the potential. This is an attraction of the particle towards lower potentials. What is the force acting on the rod? Since this is a computer simulation, time and space are discretized. The simulation would proceed in discrete timesteps Δt. How do I compute the position of the rod in each timestep? How would you generally approach this problem? Your help is greatly appreciated.