图像过颂卖(3,45),(6,0),将两点坐标代入h=v0t-1/2gt^2得:
45 = v0*3 - 1/2g*3^2 = 3v0 - 9/2 g ......(1)
0 = v0*6 - 1/2g*6^2 = 6v0 - 18 g ......(2)
由(2)得:v0=3g,将其代入(消槐1)得:
45 = 3*3g-9/2g = 9/2g
g = 10m/s^2
v0 = 3g = 30m/s
h = v0t-1/2gt^2 = 30t-5t^2
h=25
25 = 30t-5t^2
5 = 6t-t^2
t^2-6t+5 = 0
(t-1)(t-5) = 0
t1=1,t2 = 5
1秒,或5s后,物体在野桥逗离抛出点25米高的地方。
v0是物体上抛的初速度,t是物体上升的时间
h=v0t-(1/2)*gt^2
h=vt-1/2gt^2.带入v=25,h=20。t=1或4s。有两解是因冲兆弯为物体会先到猜饥该散闷点,然后从最高点下落再次经过该点。