[填空题]
At the instant a rac0bnp: 83yx vmeuwt2(gkz p(y.lb 3f,ub8x6j ve began, a 65$-\mathrm{kg}$ sprinter exerted a force of 720 N on the starting block at a 22$^{\circ}$ angle with respect to the ground. (a) What was the horizontal acceleration of the sprinter? (Keep one decimal place)
(b) If the force was exerted for 0.32 s , with what speed did the sprinter leave the starting block? (Keep one decimal place)
