Loading...

in friction or a lack of friction and energy conservation. So when a moving soccer ball, when it hits a dry pitch, for example, it actually has what we call higher transitional kinetic energy. So the friction between the dry grass blades in the ball, which is made up polyurethane, that basically acts as a powerful decelerating force. And because the friction force is applied to the bottom of the ball outside of its center of gravity, this actually also generates torque. So this torque forces the ball into a rapid rotation. And as a result, it converts a huge part of that energy into translational kinetic energy. And you get rotational kinetic energy, so topspin. And you also have thermal energy, right? The balls, there's compression energy as well, and other things elasticity. So that actually converts some of that into thermal energy. But the result of all this is that the ball loses this for velocity quickly.