posted by Sydney Wajcman .
You are riding in a school bus. As the bus rounds a flat curve at constant speed, a lunch box with a mass of 0.550 suspended from the ceiling of the bus by a string of length 1.77 is found to hang at rest relative to the bus when the string makes an angle of 31.0 with the vertical. In this position the lunch box is a distance 55.0 from the center of curvature of the curve.
What is the speed of the bus?