What is the thinnest soap film (excluding the case of zero thickness) that appears black when illuminated with light with a wavelength of 495 nm? The index of refraction of the film is 1.35, and there is air on both sides of the film.

Asled is being held at rest on a slope that makes an angle θ with the horizontal. after the sled is released, it slidesa distance d1 down the slope and then covers the distance d2 alongthe horizontal terrain before stopping. find the coefficient ofkinetic friction μk between the sled and the ground, assumingthat it is constant throughout the trip. find the coefficient of kinetic frictionμk. express your answer in terms of someor all of the variables d1, d2, and θ.