A hill is covered with snow, and has a slope of 30 degree above the horizontal. The slope is l = 40.m long. At the top of a hill, you build a cylindrical snowball, w = 10.0cm long and with a radius of ri = 2.0cm. The mass of the snowball is m = 0.11kg. The snowball is set rolling down the hill. By the time it reaches the bottom of the hill the snowball has a radius of rf = 5.0cm (but still is 10.0cm long). Assume that the snowball is still the same density throughout, and assume that the snow went on smoothly - the same thickness layer of snow from the hill stuck to the snowball at all times. How fast is the snowball rolling at the end? (Hint: use conservation of energy.)