A box of mass 1.1 kg slides down a frictionless slope and is stopped by a horizontal spring with a spring constant of k = 3100 N/m. The box changes height by a distance of 0.78 m during this process. If the box had an initial speed of 0.62 m/s, use conservation of energy to calculate

(a) The compression in the spring, when the box comes to a halt.

(b) If 6.5 J of work was done by friction as the box slides down the slope, what would be the compression in the spring?