- #26

tiny-tim

Science Advisor

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I honestly don't get this, why the force is minimum when you use the rolling constraint?

rolling is defined as a = rα

anything else isn't rolling

if you gradually decrease F (for a particular µ

_{k}) until you get rolling, the minimum F will be when rolling occurs, ie a = rα

(hmm … or maybe we should

*increase*F, and use the rolling equations, and find the value of F for which the friction equals µ

_{s}mg ? )