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M3: friction

Can someone explain this to me. I know the coefficient of friction is the force required to move the object/its weight.

I also know w = [8(pi)]/3

which way is friction acting?
(edited 5 years ago)
Original post by Maths&physics
Can someone explain this to me. I know the coefficient of friction is the force required to move the object/its weight.

I also know w = [8(pi)]/3


When the disc rotates, it will impose a radial force on the particle. As long as this force is less than (or equal to) μR\mu R, the particle will remain at rest and won't slip on the disc.

It's this inequality that will yield the least possible value of μ\mu.
Original post by RDKGames
When the disc rotates, it will impose a radial force on the particle. As long as this force is less than (or equal to) μR\mu R, the particle will remain at rest and won't slip on the disc.

It's this inequality that will yield the least possible value of μ\mu.


thanks. which direction is friction acting in?
Original post by Maths&physics
thanks. which direction is friction acting in?


Well in which direction do you think the radial force will act on the particle?? Friction will act opposite of that.
Original post by RDKGames
Well in which direction do you think the radial force will act on the particle?? Friction will act opposite of that.


ok,

so I know

Fr = uR

friction is keeping it from moving

which other force is acting on it - I assume its the force from motion?
Original post by RDKGames
It's just two forces... centripetal force, and the friction opposing it. The condition is as I've mentioned already, centripetal force \leq max friction.


Well, that makes everything clear. thanks :smile:
Original post by Maths&physics
Well, that makes everything clear. thanks :smile:


Sorry, I mispoke and realised that so I did a bit of a background check.

The centripetal force is the friction.

http://physics.bu.edu/~duffy/ns549_fall07_notes02/turntable.html

https://www.youtube.com/watch?v=WdcfWf07UIg

The video should explain it better than I can.

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