Ballistics

allistics is the scientific study of projectiles. A projectile is an object flying without engine power after it has been fired or launched. Baseballs and golf balls are projectiles. Cannonballs, bullets, and artillery shells are also projectiles. Rockets and certain types of spacecraft can be projectiles, too.

Ballistic Science

The science of ballistics was developed hundreds of years ago to help gunners figure out where their cannonballs would land. When a cannonball is fired from a cannon tilted up at an angle, it rises as it flies away from the cannon. Its upward motion is slowed down by grav­ity until it stops rising and falls back to the ground. The flight path of a projec­tile is called its trajectory.

If gravity were the only force acting on a cannonball, its path would follow a curving shape called a parabola. In fact, it falls short, because the air pushes back against it. This air resistance, called drag, slows the cannonball.

The first person to make a scientific study of ballistics was Italian mathe­matician and engineer Niccolo Fontana Tartaglia (1499-1557). Tartaglia was the first person to notice that a cannonball followed a curved path. Until he pointed this out in the 1530s, people thought a cannonball flew in a straight line.

A pointed projectile causes less drag than a ball. For this reason bullets, artillery shells, and rockets have pointed noses. A pointed projectile, however, tends to tumble as it flies through the air. Bullets and artillery shells are made to spin to stop them from tumbling and to keep them flying point first. This action is called spin stabilization. Some rockets are also spin stabilized. Large rockets, like arrows, are stabilized by tail fins.