Hi TSny!
I have consulted with some friends and I think I see the problem. I have assumed that the friction due to the ground must always be radially directed due to the simple uniform case of circular motion. However, here the centripetal force keeping the body in circular motion is provided...
Homework Statement
An object slides along the ground at speed v at the base of a circular wall of radius r. The object is in contact with both the wall and the ground, and friction acts at both contacts. The wall is vertical and provides no force in the vertical direction. (i) Show that the...