ballistic coefficient

The ballistic coefficient is a measure of a projectile's ability to coast. It is defined as Cb = M/Cd A where M is the projectile's mass and Cd A is the drag form factor. At any given velocity and air density, the deceleration of a rocket from drag is inversely proportional to this value. Intuitively, it is the principle behind why a tightly crumpled piece of paper can be thrown farther than a loosely crumpled one.