A 15.0g bullet with a speed of v=235m/s is fired into a block of wood that is initially at rest on a frictionless surface. The block of wood is attached to a horizontal massless spring with a spring constant k=195N/m that is intially uncompressed. The other end of the spring is attached to a wall. The bullet becomes embedded in the block of wood which then compresses the spring a distance of 28.0cm before momentarily coming to a stop.

a) Determine the mass of the wooden block?

b) What fraction of the kinetic energy is transformed into other forms of energy during the inelastic collision of the bullet with the wooden block?