La Fisica Nel Tennis Tavolo | Ping Pong | The Physics of Ping Pong | Science To You

La Fisica Nel Tennis Tavolo | Ping Pong | The Physics of Ping Pong | Science To You


In this video of SCIENCE TO YOU we will
show the physics laws of a very popular sport in which almost
anyone has played once: table tennis. The first thing that a physicist can note
wacthing a table tennis game is the trajectory of the ball. The path of the ball is a parabola.
This tragectory follows from the laws of a uniformly accelerated rectilinear motion
along the y-axis and a uniform rectilinear motion
along the x-axis. If you pay attention you can notice the player hitting the ball always
in the highest point of its trajectory, because at that moment the ball
only has horizontal velocity. The racket sends the ball back with
only horizontal velocity but in the opposite direction. If the ball had a vertical velocity it would
probably hit the net. The ball has an “effect” when it
rotates on itself. To rotate the ball we need to rub it
as long as possible on the rubber of the racket, thus exploiting the frictional force between
racket and ball In fact, there are many players who
choose tires with higher friction coefficients to provide the ball more spin. Now let’s briefly explain what is the magnus effect. Let the ball rotate
clockwise and move in the air flow so that it’s coming from left to right with velocity Va. Air layers close to the ball stick ton the surface and are thus stationary with respect
to the ball. (Yellow arrows). The air flow below the
ball is thus forced to follow the surface of the
ball more than the air layers do on top. According to the principle of action and reaction, if the air is
pulled towards the ball, the ball is pulled towards the layers of air. This is why
an upward force is created. (backspin) If in the same conditions of air flow
the ball rotates counterclockwise, a downward force is created (Topspin). To conclude, the magnus effect is responsible of the change of the
trajectory of a rotating body moving in a fluid. The rotation of the ball is also responsible of the change in the trajecoty direction after the collision with the table. if for example the rotation is
clockwise (backspin) the ball will go back. This due to the friction between the ball and the table. It’ evident that the smash provides
the ball to move with high speed, but why? The answer is in the definition of
impulse an impulse is the product between the force
applied and the time interval in which it is exerted I= F * (T 2 – T 1) as you can see during the
smash the force is exerted for a longer period of time
than usual. Since the impulse is equal to the change
of momentum before and after the impact, a more intense impulse
corresponds to a higher final speed. When the ball hits the paddle,
a quasi-elastic collision occurs. In fact, while the amount of momentum of the
system remains constant, the kinetic energy of the balls decreases slightly. The impact is not completely elastic
due to the rubber of the racket that converts kinetic energy into
thermal energy. To conclude, here are some examples of services.

6 Comments

  1. criscore diy attitude says:

    Hi there! Can you please submit english subtitles? That'd be more convenient either for you and for your viewers.

  2. Mario Busonero says:

    Bel video ragazzi. Vi suggerisco qualcosa del genere anche sul Badminton e gli altri sport di racchetta (tennis, squash, paddle, ecc.) che si prestano benissimo.

  3. Sakib Sheikh says:

    Bel video. Shock quando ho visto che la palestra è uguale a quella del mio liceo. XD sì, il buon vecchio Galilei.

  4. Minecraft animations says:

    grande siete grandissimi grazie a voi sono migliorato un casino a ping pong 🙂

  5. Lollochannel TV says:

    AttenZZZZione

  6. Nicolae Rusu says:

    grazie !!😃

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