A box of mass m=10.0 kg, initially at rest, is pushed by a constant horizontal force of F=25.0 N for a distance d=10.0 m before reaching the bottom of a hill. The force stops and the box slides up the hill of height h=2.0 m. It hits a spring which compresses by an amount x=2.5 meters before the box stops. a) What is the speed of the box before it climbs up the hill?

b) What is the spring constant?