Speed of compression

A box of 2 kg is sliding along a floor with speed $v_{1} = 5 m/s$ . It then runs into and compresses a spring until the box momentarily stops. Its path to the initially relaxed spring is frictionless, but as it compresses the spring, a kinetic frictional force from the floor acts on the box. The kinetic frictional coefficient is $μ_{k} = 0.5$ . The maximum of the static frictional coefficient is $μ_{s} = 0.7$ . The spring constant is k = 160 N/m . Ignore the size of the box.

calculate the speed of the box when it re-enters the frictionless floor