Modify program bal1 from Example $4.8$ to read in the initial velocity with which the ball is thrown. After modifying the program, run it with iritial velocities of $10 \mathrm{~m} / \mathrm{sec}, 20 \mathrm{~m} / \mathrm{sec}$, and $30 \mathrm{~m} / \mathrm{sec}$. What effect does changing the initial velocity $v_{0}$ have on the range of the ball? What effect does it have on the best angle $\theta$ at which to throw the ball?