Five identical balls each of mass m and radius r are string like beads at random and at rest along a smooth rigid horizontal thin rod of length L mounted between immovable supports Assume `10rleL` and that the collision between balls or between balls and supports are elastic if one ball is struck horizontally so as to acquire a speed v the average force felt by the support is

Options

A. `frac(mv^2)(2(L-nr))`
B. `frac(mv^2)(L-2nr)`
C. `frac(mv^2)(L-nr)`
D. zero