One of my favorite things to do with my friends over the summer is play pickup football. There is a lot of physics that is involved in playing the game of football. First off when the quarterback throw the football to a receiver he must apply a force to the ball so that it can travel in the air to the receiver.Whatever force he applies to the ball, the ball then applies back onto his hand. Once the ball is in the air its horizontal velocity should stay about the same(neglecting air resistance). However once it is the air, gravity then begins to apply a downward acceleration of 9.81 m/s^2 on the ball so that it can only stay in the air for a certain amount of time. Another big part of football is tackling and the contact made by players. When a defensive player tackles an offensive one, whatever force is applied onto the player getting tackled is then also applied back on the player tackling him. You can determine the momentum of the players running before based upon their masses times their velocities. You can then determine the players speed and direction after the collision based upon the total momentum because it is conserved through the collision. There is obviously a lot of physics involved in football as it takes a very important role in every aspect of the game.