Projectile Motion
If a rocket is fired straight upward, your distance to the rocket first increases, then decreases. If you fire the rocket outward (say at 30o to the horizontal), your distance is always increasing. Assuming no frictional (drag) forces on a rocket: find the maximum angle at which the rocket can be fired so your distance to the rocket never decreases.
NOTE: Your answer should not depend on either vo or the value of g, the acceleration due to gravity.