A 59.5 kg person, running horizontally with a velocity of +3.90 m/s, jumps onto a 12.2 kg sled that is initially at rest.

Question

(a) Ignoring the effects of friction during the collision, find the velocity of the sled and 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?

(1) use the momentum conservation law.

(2) Set the initial kinetic energy of the sled and passenger, (1/2) M V^2, equal to the work done against friction, which is
(mu,k)*M*g*X
M is the total mass
X = 30 m
9 = 9.8 m/s^2
V = initial velocity (from part a)
Solve for "mu,k", the coefficient of kinetic friction

Thanks!