2 (8 marks) A dart of mass m = 20 g moving at a speed v1 = 5 m/s sticks to a stationary box of mass M = 180 g. The two objects then slide into a spring (with spring constant k = 100 N/m) a distance x before they stop. The surface has a coefficient of kinetic friction k = 0.6. a) (2 marks) Determine speed vf of the two objects just after the collision. b) (6 marks) Determine the max compression of the spring x. (Hint: You'll need to use some energy skills here