Question

3. A figure skater with an angular velocity of 30 rad/s decreases her moment of inertia by a factor of 3. What is her new angular velocity assuming a frictionless surface? (2 pts)

Answer 1

as friction is not present, total angular momentum will be conserved.

angular momentum=moment of inertia*angular speed

let initial moment of inertia=I

then final moment of inertia=I/3

if final angular speed is w rad/sec,

conserving angular momentum:

initial moment of inertia*initial angular speed=final moment of inertia*final angular speed

==>I*30=(I/3)*w

==>w=30*3=90 rad/sec

hence her new angular velocity is 90 rad/sec