On a very large smooth field there are a large number - N > 1 billiard balls. The balls are located randomly, but on average they evenly fill a certain circle and do not touch each other. The same ball is introduced into this cluster from the side with a speed v, becomes entangled and sets the entire array in motion. Estimate by order of magnitude the time after which the balls will stop colliding with each other. The radius of each ball is r.

Answer. Format gif