A block of wood with a mass M=4.65 kg is resting on a horizontal surface when a bullet with a mass m=18g and moving with a speed v= 725m/sec. strikes it. The cofficient of friction between the block and the surface is =0.35. The distance the blokc moves across the surface is?

The bullet has kinetic energy \frac{M V^2}{2}. The coefficient of friction between the block and the surface consumes all of that kinetic energy. (F = \mu N where μ is the coefficient of friction and N is the "normal" (downward) force). You simply have to figure out the distance to consume that much energy.

Friction - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Friction)