解：设听到回声时船与悬崖之间的距离为s，则3s内船向悬崖前进了s1 = 5 × 3m = 15m声音运动的路程为s2 = 340 × 3m = 1020m而s2 – 2s = s1解得s = 502.5m
(340*3-5-3)/2=502.5m
