[填空题]
A world-class sprinter can burst out of the blocks to essentialxwx;bwjub9 9: ly kjp9+4+ dw-6dl5z wb7rq irgytop speed (of about 11.5 m/s) in the first 15.0 m of the 75l4 wd y9+qrg rdpki+jz6-wb race. What is the average acceleration of this sprinter, and how long does it take her to reach that speed? $\approx$ = $m/s^2$ (retain two decimal places) s
