86 g bullet moving with an initial speed of vi = 439 m/s is fired into and passes through a 1.06 kg block.

A 4.86 g bullet moving with an initial speed of vi = 439 m/s is fired into and passes through a 1.06 kg block. The block, initially at rest on a frictionless horizontal surface, is connected to a spring with a spring constant of 832 N/m. If the block moves x = 4.50 cm to the right after impact, calculate the speed at which the bullet emerges from the block.