[填空题]
At the instant a racex: zo a: ijrn( fnnuh4 3vhn)3b/cecrzn7p606 begaopyi o 5,.n,kon, 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)
