A skier of mass 61.0 kg starts from rest at the top of a ski slope of height 61.0 m. a)If frictional forces do −1.04×104 J of work on her as she descends, how fast is she going at the bottom of the slope? b)Now moving horizontally, the skier crosses a patch of soft snow, where the coefficient of friction is = 0.180. If the patch is of width 68.0 m and the average force of air resistance on the skier is 180 N, how fast is she going after crossing the patch? c)After crossing the patch of soft snow, the skier hits a snowdrift and penetrates a distance 3.00 m into it before coming to a stop. What is the average force exerted on her by the snowdrift as it stops her? I have only started attacking part a and i looked at the other parts and do not know where to start. on part a i started by using the eqquation work = .5 (mass)(velocity^2) but my answer was wrong.