Final answer:
Cannons have long barrels to provide more time for the cannon ball to reach its final velocity, for rifling to stabilize it, and to improve accuracy and range. The rifling imparts spin, stabilizing the projectile, while fortification design changed to counter cannon use in warfare.
Step-by-step explanation:
Cannons are made to have long barrels when shooting the cannon ball, ensuring that the projectile has enough time to accelerate to its final velocity and that it is stabilized by rifling within the barrel. Rifling are grooves cut into the barrel of a cannon designed to impart a spinning motion to the projectile, similar to the function they serve in rifles. This spinning stabilizes the cannon ball in flight, increasing its accuracy and range.
The longer barrel allows for a greater barrel volume in which gunpowder can expand, thus providing more time for the gasses to exert force on the projectile. Furthermore, the use of cannon had a significant impact on military strategies and the design of fortifications, leading to changes in city and fortress walls to counteract the destructive power of cannon fire.
On the battlefield, efficient access to ammunition was key, which is why cannon balls were stacked in a pyramidal arrangement for rapid accessibility during combat operations.