[填空题]
A rotating merry-go-rounfzfh .it zi7/-d makes yscd, a :g+0bgone complete revolution in 4.0 s (Fig. 8–38). (a) What is the linear speed of a child seated cgyg+ abds:,01.2 m from the center? $m/s$ (b) What is her acceleration (give components)? $m/s^2$ the center