理化國二理化

拿一隻bb槍垂直向上擊發一個從15.3m上升的氣球從發射到聽到氣球爆炸聲音需 17.5秒請問氣球上升速度(聲速340m/s

bb槍速10m/s)
S=10t(1)-0.5*g(t1)^2=15.3 h=10T(1)-5T(1)^2[打中氣球氣球離第ㄉ距離] [設g=10m/s^2 為ㄌ好算如要精確可用課本ㄉ9.8]S/T(2) T(1)=340*T(2).....(2)T(1) T(2)=17.5....(3)10T(1)-5T(1)^2 T(1)=340(17.5-T(1))這樣解出T(1) T(2) 帶回S/T(2) 就可以知道ㄌ
17.5 秒??1.75 秒??
It is a very dangerous behavior if a boy was playing the firecrackers and he didn