Why? The Science of Athletics

SOME MORE MATHEMATICS FOR ATHLETES 281 always be a recognized factor in research, while such important contributory circumstances .as the angle of elevation of the missile, the angle of throw, initial velocity, spin in the air, and the nature of the wind must always remain as uncertain and variable quantities, although they are extremely important elements. The effect of wind resistance in relation to the angle of throw has been recognized for a long time as providing two of the most important problems awaiting solution, and many authorities, actuated by the knowledge that an aeroplane takes off best against the wind, have long doubted the soundness of the contention that a following wind was of assistance to the discus thrower. It was realized also · that only experiments carried out in a wind tunnel would solve the problem of the effect of a wind against the flight of a discus and the effect of a wind following the flight of a discus. The study involved was undertaken in 1931 at the Daniel Guggenheim School of Aeronautics at New York University, U.S.A. In order to ascertain the effect of a given wind against a discus at various angles of inclination, and to determine the most advantageous angle of throw, a discus was sus– pended in a wind tunnel by means of wires attached to delicate measuring and recording instruments. By these means it was possible to chart the "drag", or ten.dency of the discus to be pushed backwards, and the "lift"; or elevating tendency, due to wind resistance against the under surface of the discus, with contingent partial vacuum behind and on top of the discus, at various angles of inclination of the missile, varying from the horizontal to the vertical and back again. In addition, slow-motion pictures were taken to determine whether the discus changed its angle of inclina– tion during flight and what ratio of revolutions was involved. Pictures taken from a distance and on a level with the arc described by the missile showed that the initial path angle and the angle of inclination to the