A playground slide is in the form of an arc of a circle that has a radius of 9.0 m. The maximum height of the slide is h = 3.6 m, and the ground is tangent to the circle (see the gure). A 20 kg child starts from rest at the top of the slide and has a speed of 6.4 m/s at the bottom. (a) What is the length of the slide? (b) What average frictional force acts on the child over this distance? If, instead of the ground, a vertical line through the top of the slide is tangent to the circle, what are (c) the length of the slide and (d) the average frictional force on the child? aihh._