What is the thinnest soap film (excluding the case of zero thickness) that appears black when illuminated with light with a wavelength of 470 nmnm ? The index of refraction of the film is 1.33, and there is air on both sides of the film.

Which of the following situations is impossible? a) an object has velocity directed east and acceleration directed east. b) an object has zero velocity but non-zero acceleration. c) an object has constant non-zero velocity and changing acceleration. d) an object has velocity directed east and acceleration directed west. e) an object has constant non-zero acceleration and changing velocity.