Stars originate as large bodies of slowly rotating gas. Because of gravity, these clumps of gas slowly decrease in size. The angular velocity of a star increases as it shrinks because of
A) conservation of angular momentum
B) conservation of linear momentum
C) conservation of energy
D) the law of universal gravitation
E) conservation of mass

Question

Quizplus · Accepted Answer

The angular velocity of the star increases as it shrinks due to the conservation of angular momentum, which states that the product of an object's moment of inertia and angular velocity must remain constant if there are no external torques acting on the object. As the star contracts, its moment of inertia decreases, causing its angular velocity to increase to conserve the product of the two values.

Stars Originate as Large Bodies of Slowly Rotating Gas