A skater rotating about a vertical axis pulls her arms inward. Ignoring all frictional effects, which of the following statements are true? Denote the magnitude of her angular velocity by `omega`, the magnitude of her angular momentum by `L`, and her kinetic energy by `E_(k)`.

Options

A. `L` is constant, `E_(k)` increases
B. `L` is constant, `omega` increases
C. `L` and `E_(k)` are both constant
D. `L` and `omega` are both constant

Answer

A, B

Explanation

`L=Iomega, E_(k)=1/2Iomega^(2)=1/2L^(2)/I`
`L=` constant `Idarr, E_(k) uarr, omegauarr`