The impact of golf balls on natural turf: a physical model of impact

A mathematical model of impact was developed using experimental data from stroboscopic photographs of impacts of golf balls with natural turf. A vertical model of impact was first considered using the Kelvin-Voigt visco-elastic solid. The surface was modelled as having two layers, the first layer having an elastic as well as a damping component, while the second layer had only a damping component. The model was then modified for oblique impacts including the coefficient of friction to account for the effects of spin. Good agreement was found between the model and experimental data. Discrepancies were thought t be caused by the dependence of the coefficient of friction of the velocity of the ball. The model was used to predict the outcomes of 5-iron and 9-iron shots with a variety of backspins.