A boy weighing 100 lb runs and jumps on his 20-lb sled with a horizontal velocity of

Question:

A boy weighing 100 lb runs and jumps on his 20-lb sled with a horizontal velocity of 15 ft/sec. If the sled and boy coast 80 ft on the level snow before coming to rest, compute the coefficient of kinetic friction μ_k between the snow and the runners of the sled.