0 g bullet is fired horizontally into a 104 g wooden block that is initially at rest on a frictionless horizontal surface and connected to a spring...

A 12.0 g bullet is fired horizontally into a 104 g wooden block that is initially at rest on a frictionless horizontal surface and connected to a spring of constant 141 N/m. The bullet becomes embedded in the block. If the bullet-block system compresses the spring by a maximum of 78.0 cm, what was the speed of the bullet at impact with the block?