．There is a figure skater who can rotate around its own vertical axis. At the beginning, her arms were straightened. At this time, the moment of inertia was J0 and the angular velocity was w0(picture). Then she retracted her arms so that her moment of inertia became one-half of the original, then her angular velocity of rotation would become________

．There is a figure skater who can rotate around its own vertical axis. At the beginning, her arms were straightened. At this time, the moment of inertia was J0 and the angular velocity was w0(picture). Then she retracted her arms so that her moment of inertia became one-half of the original, then her angular velocity of rotation would become________