Two children are sliding down a snowy hill which is inclined by 43.5 degrees with respect to horizontal. One has a rough sled which has a coefficient of kinetic friction between it and the snow of μ?k = 0.374; the other has a slippery sled which has a coefficient of kinetic friction between it and the snow of μ?k= 0.142. If both children start at the top of the 41.2 m tall hill initially at rest, what is the difference in speed between these two sleds at the bottom of the hill?