Collison problem, bullet embeds itself inself in a block

[rk1991]

Homework Statement

A bullet of mass 0.125 kg traveling horizontally at a speed of 150 m/s embeds itself in a block of mass 2.5 kg that is sitting at rest on a nearly frictionless surface.

What is the speed of the block after the bullet embeds itself in the block?

Homework Equations

The Attempt at a Solution

 

[AEM]

Conservation of momentum will get you started.