Question

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?

Answer 1

The law of conservation of angular momentum holds because the cloud is collapsing only due to gravity.Because angular momentum is proportional to velocity times radius, keeping this product constant requires that the velocity of rotation increase when the cloud radius decreases. Hope it helps.