A 0.396-kg block is attached to a horizontal spring that is at its equilibrium length, and whose force constant is 18.5 N/m. The blockrests on a frictionless surface. An arrow with a mass of 0.0500 kg is shot horizontally at the block, hitting it with an initial speed of 2.02 m/s and sticking. How far does the block-arrow system compress the spring?