1. The problem statement, all variables and given/known data A train traveling at a constant speed rounds a curve of radius 218 m. A lamp suspended from the ceiling swings out to an angle of 16.6° throughout the curve. What is the speed of the train? 2. Relevant equations mv^2/r 3. The attempt at a solution I drew a diagram and attempted to calculate v by setting mv^2/r = -cos16.6 mg I don't really know how to approach this?