An ice skater spinning with outstreched arms has an angular sped of 4.0 rad/s. She tucks her arms in, decreasing her moment of inertia by 7.5%.
(A) what is the resulting angular speed?
(B) By what factor does the skater's kinectic energy change? (neglect any frictional effects)
(C) Where does the extra kinectic energy come from?