A gun is fired vertically into a 1.55 kg block of wood at rest directly above it. If the bullet has a mass of 21.0 g and a speed of 190 m/s, how high will the block rise into the air after the bullet becomes embedded in it?

Question

i don't even know where to begin... would it have something to do with 1/2mv^2=mgh?

Yes! The kinetic energy of the block and embedded bullet gets converted to potential energy when in reaches its maximum height. Do you know how to get the kinetic energy of the block + bullet?

i don't think so, could you add the masses for m?

This is conservation of momentum. The momentum of the bullet before it hits the block has to equal the momentum of the bullet + block. This will give you the velocity of the bullet + block. Then, you can calulate its kinetic energy!!

thanks!