Abstract

The paper presents in a general way the factors shaping the rotationless motion trajectory of a ball. Taking into account the aerodynamic characteristic Cx = f (Re) for the near-critical Reynolds numbers the examples ofsolutions of the motion equations for a ball are given, where the ball considered is a volley ball with diameter D = 0.21 m and mass m = 0.27 kg, having initial verlocity VO = 21.3 m/s., height y0 = 1.8 m, and varying initial angles alpha 0 = 10 degress, 15 degrees, 20 degrees, 25 degrees and 30 degrees. The results obtained are given in the form of motion parameter diagrams, commented with regard to ball trajectory after service. It is shown that within the range of motion parameter values analysed there may occur their abrupt changes making returning more difficult. Verf.-Referat