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Re: Rolling, Static, and Kinetic Friction

David Bowman wrote:
Since when is the dynamical effect the same? Static friction is a force
of constraint that prevents relative motion parallel to two contacting
surfaces and which dissipates no energy. Various kinetic frictions (i.e.
rolling, sliding, etc.) provide no constraint and *do* dissipate energy. This
is a *significant* difference--even for high school students.

Why do you say kinetic frictions supply no constraint?