RoughSalad

RoughSalad t1_it37t9b wrote

A perfectly round wheel won't roll frictionless/forever - unless you find an infinitely stiff surface to roll on, that is. A single point/line of contact will create infinite pressure, the wheel will sink in until the surface can support the weight. Along the area of contact we now have forces of adhesion, and moving the depression to roll forward will take up energy as well.

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