A rugby ball is oval-shaped and so behaves in a very unpredictable way.
Easy to hold against the body and throw to a teammate, the ball follows a specific trajectory at several key moments in the game. VIDEOGRAPHIC
Easy to hold against the body and throw to a teammate, the ball follows a specific trajectory at several key moments in the game. VIDEOGRAPHIC
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00:00 A rugby ball is oval shaped and so behaves in a very unpredictable way.
00:12 Easy to hold against the body and throw to a teammate, the ball follows a specific trajectory
00:17 at several key moments in the game.
00:19 When passing, a player causes the ball to rotate on its axis.
00:23 This is called a spin pass.
00:25 The ball continues on this axis, following a rectilinear and precise trajectory.
00:30 In physics, this is called the law of conservation of angular momentum.
00:35 When the ball is kicked as in a penalty, the trajectory is not symmetrical.
00:39 It does not describe a parabola, but rather what's known as a Tartaglia movement.
00:44 This has two phases.
00:46 In the first phase, the ball benefits from the speed generated by the kick itself.
00:51 In the second, ball speed is reduced dramatically and it drops like a stone.
00:57 In this phase, players take into account the wind which can affect the trajectory and speed
01:02 of the ball.
01:04 Just as it does when passed, the ball when kicked benefits from a gyroscopic effect during
01:09 its trajectory.
01:11 Carry improves and it flies further, up to 15%.
01:16 There's also the Magnus effect, when the ball rotates on its own axis, causing turbulence.
01:21 Ahead, air pushes the ball, while behind, a turbulent space slows it down.
01:27 Hence the curved trajectory in the shape of a banana, which helps it pass between the
01:31 posts.
01:32 [END]