Difference between projectile motion and linear motion?

hmm lets see

well I guess (yes this is a guess ^_^) they are both similar because an object is accelerated and moves in space. Projectile motion would be motion given to something, but that object will decelerate eventually (like a bullet, it loses momentum). Linear motion might therefore be like a constant movement in a direction at a speed with no deceleration ( like a car maintaining its speed along a highway)