(1)求点B的海拔高度;
-(174.8-0.4m*120m/10m)=-170m
(2)若点C在点A的正上方,海拔高度为-68.8m每垂直升高10m用30s,求从点A到点C所用的时间.
30s*[-68.8m-(-174.8m)]/10m=318s
(1)求点B的海拔高度;
-(174.8-0.4m*120m/10m)=-170m
(2)若点C在点A的正上方,海拔高度为-68.8m每垂直升高10m用30s,求从点A到点C所用的时间.
30s*[-68.8m-(-174.8m)]/10m=318s