1. The problem statement, all variables and given/known data A skateboarder with mass 61kg sliding down a circular ramp reaches a speed of 7.8 m/s at the bottom of the ramp what is the net force acting on the skateboarder at that point? 2. Relevant equations N = mg Fr = m * v^2/r 3. The attempt at a solution In my opinion the only force acting on the skateboarder at the bottom of the ramp is the NORMAL force which is m*g = 597N but since the answer in the book is 1127 it seems it takes into account some fictional centrepintal force which is m * v^2/r = 530 530+597 = 1127 however as far as I can tell there is no actual force pulling him inward towards the center of the ramp but and the only reason he stays in a "circular motion" at that point is the solid ramp preventing his escape, now if we were at the top of the ramp it would have been a different matter. I also have a second question deriving from this one, if I were asked what are the net forces acting on this skateboarder not at the bottom or the top, but rather at an angle, say 30 degrees from center where 0 is the bottom. infact if someone could explain all kinds of degrees,say... 30, 90 and 130? how do I even aproach that?