I am almost done in my research on golf balls, however I found something unusual which I can't seem to find an explanation for. After collecting data on a golf swing (golf ball speed, club head speed, backspin, distance etc.) I created a few graphs. Once of them was a force vs distance graph (shown below). Now, the golf balls I tested were rated 72 (Callaway HX Diablo), 88 (Pinnacle lady), 98 (Titleist Pro V1) and a smooth golf ball from Caesar golf. http://cdn.thesandtrap.com/e/ef/efa9d536_unusual.jpeg [Broken] Basically from interpreting the graph, the more compressible golf ball (72) needs more force upon impact than a less compressible ball (98) at low speeds to travel the same distance. However, at higher speeds the 72 rating golf ball needs less force to travel the same distance as the 98 rating golf ball (black line below the green line above 720kg). For the upper portion of the graph, the results make sense, except for the lower portion it doesn't. Does anyone have an idea why the graph looks like it is? I initially thought of the deformation energy lost to the ball upon impact at low speed, however that would also occur at higher speeds too. Maybe at higher speeds more energy is translated to the kinetic energy of the ball and at lower speeds its lost to the deformation energy of the ball. However I feel that makes no sense at all. I just cant seem to come up with a viable explanation. I also thought the results were wrong but maybe they are not. Anyone has any suggestions to the reason why the graph looks as it is?