A bullet of mass \(0.02\,kg\) travelling horizontally with velocity \(250\,m\,s^{-1}\) strikes a block of wood of mass \(0.23\,kg\) which rests on a rough horizontal surface. After the impact, the block and bullet move together and come to rest after travelling a distance of \(40\,m\). The coefficient of kinetic friction on the rough surface is \((g = 9.8\,m\,s^{-2})\)