An airplane is flying horizontally at a constant speed j and height h. A gun is located at the origin (0,0). At t=0, the airplane is at (0,h). A shell is fired from the gun with an initial muzzle velo

Step 1: Define the position equations for the airplane and the shell.
Let the gun be at the origin $(0,0)$. The airplane is initially at $(0,h)$ at time $t=0$.
The airplane flies at a constant speed $j$ horizontally. Its position at time $t$ is:

$$x_A(t) = j t$$ $$y_A(t) = h$$

The shell is fired from the gun with an initial muzzle velocity $v$ at an angle $\theta$ with the horizontal. Its position at time $t$ is:

$$x_S(t) = (v \cos \theta) t$$ $$$$