A 60.0 kg person, running horizontally with a velocity of 3.80 m/s to the right, jumps onto a 12.0 kg sled that is initially at rest. (a) Ignorning the effects of friction during the collision, find the velocity of the sled and the person as they move away. (b) The sled and person coast 30.0 m on level snow before coming to rest. What is the coefficient of kinetic friction between the sled and the snow?