Why? The Science of Athletics

SOME MORE MATHEMATICS FOR ATHLETES 285 winds up to r4/r5 m.p.h. and should throw with an angle of inclination of 35 degrees and an identical initial path when the adverse wind does not exceed 8 m.p.h. Secondly, when throwing against a wind of over 8 m .p .h. he should decrease the angle of inclination to decrease the "drag" by lessening the surface offered for wind resistance. At the same time he should rely upon his cumulative momentum and the velocity of projection generated in the explosive "jerk", mentioned earlier, as the main contributory factors for getting distance in the throw. Thirdly, it must be remembered that the athlete has a go degrees sector into which to throw his discus, and when the head,-wind is over 14 m.p.h. he should throw in such a direction as will enable him to use a quartering wind ; but in that case he must give the discus a flatter angle of inclination. Fourthly, if the existing circumstances compel him to throw with a following wind he should make his delivery at a nearly vertical angle of inclination and throw the discus high, so that the wind pressure from behind may bear against an almost vertical face, thus partly neutral– izing the loss of vacuum, while taking advantage of the propulsive force of the following wind. Angles of Projection of Missiles We have noted already that the proper angle of projection for th~ javelin, shot and hammer is one of approximately 45 degrees, and that of the discus 35 degrees in ideal conditions. Most athletes know that these are the correct angles of delivery, and yet how seldom one sees the discus and javelin throwers getting their implements away along the proper parabola of flight. When a discus is thrown properly it rises from the thrower's hand with its whole face inclined to the ground at an angle of 35 degrees for some few feet and then tips slightly inclined inward to the left until it flattens out at the topmost point of its parabola o~ flight. Then gravity exerts its power and the fall of the d1scus earthwards is accelerated. 1f a perfect throw has been made the discus will follow the rest of its downward