A girl of 50 kg slides down a 8 m long slide into a pool. The upper end of the slide is 4.0 m above the water and the lower end of the slide is at the level of the water. Assume a coefficient of friction of 0.20, find: a) the potential energy of the girl at the start of her slide, b) the force due to friction, c) the energy loss in overcoming friction, d) maximum kinetic energy of the girl, e) the girls maximum velocity.