[填空题]
What is the angular momentum *2o b1g(wro z:rtfoi8*iwv3yo1kl. sof a 0.210-kg ball rotatingx0 auo5fgsj gs/u7 u(vo. nwk/jj y4,7 on the end of a thin string in a circle of radius 1.wf,x/o/5jgju4nvk7a. 0yjg7 ss o u(u10 m at an angular speed of 10.4 $rad/s$? $kg \cdot m^2$