[填空题]
A 4.2-m-diameter merry-go-round is rotati.rk 7 m:m-hh7cg tgu0vng freelykyl g s,ge7yv;c;a: :f with an angular velocity of 0elsay7::yf,kg; ;gcv .8 $rad/s$ Its total moment of inertia is 1760 $kg \cdot m^2$ Four people standing on the ground, each of mass 65 kg, suddenly step onto the edge of the merry-go-round. What is the angular velocity of the merry-go-round now? $rad/s$ What if the people were on it initially and then jumped off in a radial direction (relative to the merry-go-round)? $rad/s$