A skateboard track has the form of a circular arc with a 3.20 m radius, extending to an angle of 90.0° relative to the vertical on either side of the lowest point, as shown in Figure 8-24. A 67.0 kg skateboarder starts from rest at the top of the circular arc

Answer 1

OK, so it is a "half pipe".
What is the question?

http://www.ehow.com/how_6467235_ride-half-pipe-skateboard.html