The weight, size and amount of air pressure in a ball affect how it moves through the air. As these qualities tend to be strictly regulated by soccer leagues, however, any change in how far a ball can fly likely arises from its padding. With thicker, softer padding affecting both its initial speed and the impact of wind resistance, a soccer ball's flight can change greatly with different types of padding.
Forces
When you kick a ball at rest, a number of forces affect how it moves. The first is the force that you put into the ball with your kick. Once moving, there are two major forces that limit its distance whether it goes into the air or travels on the ground. Otherwise known as wind resistance or drag, the force of air friction acts in the opposite direction of the ball's movement. While on the ground, surface friction further hinders the ball's ability to travel long distance. Despite the absence of surface friction, a ball traveling in the air must combat the force of gravity to maintain its flight over a long distance. Aside from gravity, all of these forces affecting a ball's distance change with the padding of the ball.
Initial Kick
According to the law of conservation of energy, the energy in your foot as you kick transfers to the ball upon impact. This is what provides the ball with its initial force, allowing it to either roll or fly through the air. While most of this energy transfers to the ball, some of it is lost to sound and the deformation of the ball. With two balls of equal mass, size and air pressure, a ball with thicker padding deforms more upon impact. Although this slight denting is short-lived, a greater amount of padding decreases the distance that the ball travels due to energy lost to deforming the ball.
Air Friction
Even if you manage to launch two balls at the same initial speed, the amount of padding on a ball will affect its distance. Similar to the effect that your foot has on the ball's surface, the opposing force of air friction slightly deforms the ball's surface. As a ball with a harder surface is better able to maintain its shape during flight, it will lose little energy to deformation in the air. In contrast, balls with more padding lose a considerable amount of energy to changes in shape, thus limiting their potential distance.
Normal Force and Bounce
Whether rolling, bouncing or touching down after a long flight, a ball with thick padding does not travel as far as a lightly padded ball. All of this arises from loss of energy due to changes in shape. This deformation is due to the normal force, which is a force that acts in the opposite direction of gravity as a ball rolls along and constantly presses against a surface. As balls with thick padding deform more when they bounce and roll, they lose more energy to changes in shape than balls with less padding. As such, thickly padded balls are not able to roll as far or bounce as high as those with harder, thinner surfaces.
References
- Physics Classroom: Horizontally Launched Projectile Problems
- University of North Carolina; The Physics of Soccer; Pooja Shah et al.; April 2004
- Physics Classroom: Initial Velocity Components
- Thephysicsofhockey.com; Speed and Energy of Projectiles in Sports; Alain Haché; 2006
- NASA: Forces on a Soccer Ball
- Serious Soccer: The Physics of Kicking a Soccer Ball