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Caw

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**Summary::**Just want to know if I'm on the right track with this question.

Hi, so this is what I have for my assignment:

A washing machines drum is rotating rapidly about a vertical axis (a so-called toploader). A wet sock is stuck on the inside, halfway up the drum, and the drum begins to slow its rotation. How many rotations per second is the drum making when the sock falls to the bottom of the drum? The coefficient of static friction between the sock and the drum is 0.21, and the drum radius is 0.32 m.

And after deriving some formula, I got these statements:

- Sock falls when Fc<Fg

=> Fg=mac+Ffr

where Fc is centripetal force

m is mass

ac is centripetal acceleration

Ffr is force friction

- From Fg=mac+Ffr, I got: mg=mac+umg

then: mg=(mv^2)/r + umg

finally: v=squrt[(g-ug)r]

- Then I used the velocity to find rotation/sec

I just want to know if I'm on the right track. And if I'm not where should I start because I have no other clue. Thank you in advance!