Observations show that interstellar clouds can have almost any shape and, if they are rotating at all, their rotation is not perceptible. however, as shown in the video, the nebular theory predicts that a cloud will rotate rapidly once it shrinks to a small size. what physical law explains why a cloud will rotate rapidly as it collapses?

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.