A ballet dancer spins about a vertical axis at 120 rpm with arms outstretched. With her arms folded, the moment of inertia about the axis of rotation decreases by 4%. Calculate the new rate of rotation.

A ballet dancer spins about a vertical axis at 120 rpm with arms outst

1.	A ballet dancer spins about a vertical axis at 120 rpm with arms outstretched. With her arms folded, the moment of inertia about the axis of rotation decreases by 4%. Calculate the new rate of rotation.
Answer» Solution :`n_(1)=120` rpm, `n_(2)=?` `I_(1(omega_(1)=I_(2)omega_(2)` LET `I_(1)=100` units , then `I_(2)=60` units `100xx120=60xxomega_(2)` `omega_(2)=200`rpm