What is the shape of cannon ball's trajectory?

Answer 1

Due to gravity, all projectiles will form an "arc" (curve) while in flight; but will not be visiable to the eye (only by studying the target). Howitzers & mortars have visable arcs, they are designed for indirect fire (target cannot be seen) and can lob shells over hills & forests (jungles). Guns are direct fire cannons and have the least arc; these are predominately mounted on warships. Naval guns (also known as rifles) aim at their target (another warship) and fire, just like an infantryman does with his rifle. The longer the range, the more arc.

Tank guns are copied from naval guns and are fired the same way; direct fire. The first tank guns were naval guns; as only the navy had cannon capable of being fired from within an enclosed turret. The army only had "field pieces" which rolled backwards upon firing (later they had recoil mechanisms).

In addition, traditional cannonballs (as fired from old-style muzzel-loading pieces such at the prototypical Napoleon field piece) were fired in particular manner when used against infantry targets. The basic trajectory was a flat arc, as normal for a ballistic object. However, as the target was a mass of infantry, it was found that the way to produce the most casualties was to "skip" the cannonball into the infantry - that is, rather than fire the cannonball so as to try to directly hit the infantry mass, the point was to allow the cannonball to hit several dozen yards in advance of the infantry. If the ground was sufficiently firm, the velocity and spin on the cannonball would make it bounce, in a manner similar to a flat stone being skipped across a pond. This meant that the cannonball would cut a large path through the infantry formation, rather than just hitting a small number of people. In this context, the shape of the cannonball's tragectory is a series of connected arches, rather than a single arch from cannon to target.