A projectile is any object thrown by the exertion of a force. It can also be defined as an object launched into the space and allowed to move free under the influence of gravity and air resistance. Although any object in motion through space (for example a thrown baseball, kicked football, fired bullet, thrown arrow, stone released from catapult) may be called projectiles, they are commonly found in warfare and sports. Mathematical equations of motion are used to analyze projectile trajectories.