在竖直方向上有:△y=gT2,解得T=
=
△y g
s=0.1s,
0.25?0.15 10
则平抛运动的初速度v0=
=x t
m/s=1m/s,0.1 0.1
B点的竖直分速度vyB=
=yAC 2T
m/s=2m/s,0.4 0.2
则抛出点到B点的时间tB=
=vyB g
s=0.2s,所以抛出点与B点的水平位移xB=v0tB=1×0.2m=0.2m=20cm,yB=2 10
gtB2=1 2
×10×0.04m=0.2m=20cm,1 2
可知抛出点的坐标为(-10cm,-5cm).故B、C正确,A、D错误.
故选:BC