5 box slides down a 4.7- -high frictionless hill, starting from rest, across a 1.6- -wide horizontal surface, then hits a horizontal spring with...

A 4.5 box slides down a 4.7- -high frictionless hill, starting from rest, across a 1.6- -wide horizontal surface, then hits a horizontal spring with spring constant 550 . The other end of the spring is anchored against a wall. The ground under the spring is frictionless, but the 1.6--long horizontal surface is rough. The coefficient of kinetic friction of the box on this surface is 0.26.