A 0.020-kg bullet traveling at a speed of 300 m/s embeds in a 1.0-kg wooden block resting on a horizontal surface. The block slides horizontally 4.0 m on a surface before stopping. What is the coefficient of friction between the block and the surface?

I know the formula for kinetic friction, but I don't know what to do with the bit about how far it slides. Any help would be greatly appreciated.