1. The problem statement, all variables and given/known data A wheel is pulled over a frictionless washboard surface with a constant horizontal velocity component. The equation of the surface is y=Acos(2πx/λ) where A is the height of the surface and x is the horizontal distance along the surface. At what value v_x does the wheel begin to lose contact with the surface, and at what point on the surface will this occur? (assume the radius of the wheel <<λ) 2. Relevant equations not sure 3. The attempt at a solution I wasn't quite sure where to start on this one. I played around with the chain rule (dy/dx) (dx/dt) but didn't get any promising results. If anybody can provide insight on this one, I'd certainly appreciate it.