A bullet of 5 g, moving with an initial speed of 400 m/s, is fired into and passes via a 1kg block. The block, initially at rest on the frictionless, horizontal surface, is joined to a spring of force constant 900 N/m. When the block moves 5 cm to the right after impact, determine: i) the speed at which the bullet emerges from the block. ii) The mechanical energy lost in the collision.