1. The problem statement, all variables and given/known data A small block of mass m is sliding around the inside of an L-shaped track of radius r. The bottom of the track is frictionless; the coefficient of kinetic friction and the wall of the track is μk. The block's speed is v0 at t0=0. Find an expression for the block's speed at a time t. 2. Relevant equations 3. The attempt at a solution I'm not sure if my procedure is right. I think that the forces acting on the block on the three modified coordinate system are as follows: For the z-axis (up and down) we have the normal force and the weight of the block, and this net force ends up being zero. For the r-axis, we have that a normal force is the one that causes the centripetal acceleration (however, is it the same in magnitude as the normal force upwards?). And finally, in the tangential direction, we would have kinetic friction opposite in the direction of the block. As well, I'm not sure which is the velocity we need to find (tangential or centripetal or the combined velocity?). I think that the radial and tangential acceleration can give us the magnitude of the total acceleration of the block, and then find the velocity at a time t based on this "general" acceleration. Thank you very much in advance.