However, with the help of powerful computers, numeric solutions to these equations have been found up to now for very specific configurations only. Generally those forces and moments must be determined experimentally, and this is done by shooting experiments and wind tunnel tests. Generally, a body moving through the atmosphere is affected by a variety of forces. A second group of forces is called aerodynamic forces . These forces result from the interaction of the flowfield with the bullet and depend on the shape and surface roughness of the body.
Some aerodynamic forces depend on either yaw or spin or both.
A summary of the most important forces affecting a bullet's motion through the atmosphere is shown in the table. However, the following discussion will be restricted only to drag, lift and the Magnus force. The Coriolis force and the centrifugal force automatically arise from the fact that the earth is not resting, but rotates about an axis. The name lift suggests an upward directed force, which is true for a climbing airplane. Thus a better word for lift force could be cross-wind force .