Ball trajectories. Factors influencing the flight of the ball

No input data. – 8 p.A good tennis player knows instinctively how hard to hit a ball and at what angle to get the ball over the net and into the court so that the ball lands at just the right spot. This comes from years of practice. Players might be surprised to know just what they are doing in terms of the actual ball trajectories. For example suppose you hit a forehand at the baseline so that the ball lands on your opponent's baseline 78 feet away. If you hit the same ball but 1% faster it will land 18 inches beyond the baseline. If you hit the ball one degree higher it will land about 6 feet beyond the baseline, depending on the initial speed and angle. If you hit the ball one degree further to the left it will land 16 inches further to the left. When serving a ball at moderate to high speed, the ball must be served a few degrees down from the horizontal. Too far down and the ball will hit the net. Not enough and the ball will be long. The range of possible angles is only about two degrees, and it gets smaller if the ball is served faster or by a shorter player (Brody, 1987). The range of angles increases if the ball is served with topspin. Typical ball trajectories are shown below, together with an explanation of the trajectories.