A train travels at a constant speed around a curve of radius 225 m. A ceiling lamp at the end of a light cord swings out to an angle of 20.0º throughout the turn.

Question

A train travels at a constant speed around a curve of radius 225 m. A ceiling lamp at the end of a light cord swings out to an angle of 20.0º throughout the turn. 
Draw a free body diagram? 
What is the speed of the train?

drwls · Accepted Answer

Let the cord tension be T T*cos20 = M*g T*sin20 = M*V^2/R Divide one equation by the other to eliminate T. tan20*g*R = V^2 Solve for V V = 28.3 m/s