When a sporting projectile is set into a motion by, say, the impact of the racket, club, bat or the kick from a foot, it will travel through some medium. The displacement of the medium as the projectile follows along the path, produces reactive force on the projectile. This force acts to slow down the projectile. The reactive force that impedes the motion is called drag force. However, drag force is not the only force that acts on projectile during motion. Due to the irregular shape of the object and path taken by the projectile, the vector component of the force which acts in vertical yet in opposite direction to gravitational force, called as lift force also acting simultaneously.
Mathematical model of the rotational speed attained by the sphere after an impact from a tennis racket, requires to take into account the drag and lift forces acting on it. when the racket held at an angle brushes the ball during a impact , it causes sphere to rotate. The velocity with which it rotates and after impact with the tennis court can unpredictably change the trajectory path during the second flight depending upon the direction of the forces acting upon it. This trajectory depends upon the co-efficients of the drag and lift forces on the sphere which are function of the speed of the ball, Air-density, diameter of the ball.
Since air-density and diameter of the ball are controlled variables, the rotational speed of the ball with which it strikes the ground and bounces off with a spin causes the sphere to take up a new trajectory from that of a trajectory taken after the impact from the tennis racket. Angle at which the ball was brushed off by racket, becomes the primary factor in time gain achieved through the degree of unpredictability in bounce flight after the rotating sphere hits the ground and takes up varied rotational speed.
Comments