Some children go tobogganing on an icy hill. The start from rest at the top of the hill as shown in the diagram. The toboggan and children have a combined mass of 90 kg. If friction is small enough to be ignored, determine: a) the total mechanical energy of the toboggan at Hill A. b) the speed of the toboggan at Hill B. (3 marks) c) the speed of the toboggan at Hill C. (2 marks) Distance/Height: Hill A=20m Hill B=10m