Calculating Muzzle Speed with Embedded Bullet and Friction

[chris568]

i really need help with this- i partially understand it, but I'm not sure exactly how to do this problem.

a 44 g bullet strikes and becomes embedded in a 1.54 kg block fo wood placed on a horizontal surface just in front of the gun. if the coefficient of friction between the block and surface is equal to .28 and the impact drives the block a distance of 18 m before it comes to rest, what was the muzzle speed of the bullet?

can anyone help?

 

[andrewchang]

use energy and momentum. what collison happens?

 

[chris568]

i realize that impulse equals force times the change in time, which equals momentum, but i don't know how to apply these when there are two masses, and the coefficient of friction is involved. in all my previous problems, the necessary info was less and easier... :-\