Mentor Note -- thread moved from the technical forums, so no HH Tempate is shown...>> 1. (10 points) A pendulum of length l = 39 cm is suspended in a railway car. At what train speed would the pendulum be oscillating with largest amplitude ? The length of the rails is l = 25 m. I am just not sure what the question is asking :-/ Why would the pendulum oscillate if the train was moving at a constant velocity? It doesn't specify an acceleration, and I don't know what they mean by specifying the "length of rails." Please, I am really lost on this one.