Movment of the table tennis ball consists of speed and spin. You can see the speed, but not the spin.
But, it seems to be hear the voice saying “No, I can see the Rotation”.
However, there is no time to see the spin in a short moment of the rally.
Our body is in response to only the speed. Until recently I thought that it was normal.
However, I have changed this thought through games with better players.
They say that they can tell the spin by the arc and the mark on a spinning ball.
Since then, I began to think that it was also important to get the information of spin from that.
Now, in dynamics, the momentum is expressed by multiplying the mass (weight) and speed of the ball. It represents the momentum possessed by the ball. Also, the product of the mass and rotational speed multiplied by the radius of the ball is expressed as the angular momentum, which represents the momentum of spin. The momentum of spin is converted to the momentum of flying by the friction of racket rubber, and vice versa.
"Momentum of spin" ⇔ "Momentum of flying"