[单选题]
A pilot makes an outside vkd(4;q3 oan*zrmtbm-npp (+rertical loop /,h)tv2cd c nm(in which the center of the loop is beneath him) of radius 3200 m. At the top of his loop he is pushing down on his seat with only one-half of his nor/ 2)v dn,cmcthmal weight. How fast is he going?
