[填空题]
A horizontal force of 210 N is exerted on a q1.n ke 1da/;e0s /ku famopf 0msy/5f2.0-kg discus asuk u s vo ;p6,r1dukzm tgm7l79e-sn+, it rotates uniformly in a horizontal circle (at arm’s length) of radius 0.90 m. Calculate the speed og sz+m7e nk,o-p;,6ktsl m9uuv 17u drf the discus.
