A 5 kg object is spun around a radius of 1.3 m and makes 9 rotations in 45 seconds. a. what is the period of rotation?
b. if the object's velocity is 25 m/s, what is it's acceleration?
c. What is the net force acting on it?

What is the thinnest soap film (excluding the case of zero thickness) that appears black when illuminated with light with a wavelength of 480 ? the index of refraction of the film is 1.34, and there is air on both sides of the film. express your answer in nanometers. hint 1. how to approach th