原题英文的大意我翻出来附原文大意是斜抛向上60°最后落在上方直线距离0.8m处Atwhatspeedshouldanarcherfishspitthewatertoshootdownafloatinginsectlocatedatadistance0.800mfromthefish?Assumethatthef

Question

原题英文的 大意我翻出来 附原文
大意是斜抛向上60° 最后落在上方直线距离0.8m处
At what speed should an archerfish spit the water to shoot down a floating insect located at a distance 0.800m from the fish?Assume that the fish is located very close to the surface of the pond and spits the water at an angle 60° above the water surface.

Answer 1

设时间为t,将初速度分解为水平方向和竖直方向,
列方程：
v*0.5*t=0.8
/3*v*t-0.5*g*t^2=0
其中*为乘号,/3为根号3,t^2为t平方
解得v=5//3(5除以根号3)=2.887