[填空题]
A rotating merry-go-roun:q xernie7(o-d mwlfw4i 3akam.9at v. 9akes one complete revolution in 4.0 s (Fig. 8–38). (a) What is the linear speed of a child seated 1.2 m from the cea9fw.ai .k vawmt93l4nter? $m/s$ (b) What is her acceleration (give components)? $m/s^2$ the center