 In this video, we'll discuss projectile motion, and by separating out the horizontal and the vertical components of that motion, we'll derive the acceleration, the velocity and the displacement of an object undergoing projectile motion. Projectile motion occurs when a moving object is subject to a constant gravitational force, and no other forces are acting on the object. This is the type of motion that basically any object travelling through the air will undergo. This is motion we all intuitively understand, even our furry friends, at least when a treat is on the line. We know that if we throw an object up into the air, it will rise continuously to a maximum height, then fall continuously until reaching a surface or the ground. We know that if we throw the same object at a steeper or shallower angle from the horizontal, and we want the object to reach the same location, then we can throw the object at a different speed to affect its motion. Of course, if I want to reach the greatest height at the same speed, I know that I need to throw the same object straight upwards. To experience projectile motion, we also don't need to throw the object upwards. The object still undergoes projectile motion if it's thrown at an angle below the horizontal. And, if I'm feeling very immune to my diligent assistant, I can even drop the object onto the ground, and we still have the conditions for projectile motion. The only force acting is gravity. Of course in this, and in most projectile motion, problems will neglect air resistance. So, when the object leaves my hand, what other force is acting on it? Well, from the definition of projectile motion, the only force acting on the object is the force due to gravity.