A wheel is rotating freely with an angular speed of 20 rad/s on a shaft whose moment of inertia is negligible.A second identical wheel,initially at rest,is suddenly coupled to the same shaft.The angular speed of the coupled wheels is
A)10 rad/s
B)14 rad/s
C)20 rad/s
D)28 rad/s
E)40 rad/s

Question

Quizplus · Accepted Answer

The angular momentum before and after coupling remains constant due to the conservation of angular momentum. Since the moment of inertia doubles when the second identical wheel is added, the angular speed halves to 10 rad/s.

A Wheel Is Rotating Freely with an Angular Speed of 20