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M3 Circular Motion

I'm a little confused with part b) of Ex. G question 7:

https://4cb73c3e1ece319eea2c1a4396b14ef67b730db9.googledrive.com/host/0B1ZiqBksUHNYNTV6bzBZYWJpMW8/CH4.pdf

I'm not sure why the resultant force can be greater or smaller than the centripetal force. How can the CF have a different value to the resultant forces causing it?

Thanks for any help!
Slipping in this instance refers to the particle rolling inwards towards the axis of rotation as opposed to remaining static at 3/5 a units away. Peace.
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φM23
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Original post by WhiteGroupMaths
Slipping in this instance refers to the particle rolling inwards towards the axis of rotation as opposed to remaining static at 3/5 a units away. Peace.


Thanks for your reply.

I still don't understand how the centripetal force can have a different value to the resultant force caused by the friction and the tension
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@TeeEm
Original post by PhyM23
Thanks for your reply.

I still don't understand how the centripetal force can have a different value to the resultant force caused by the friction and the tension

I don't understand what you're trying to say here, or how it relates to the question. Which resultant force are you thinking of?
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Original post by PhyM23


what seems to be the problem?
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Original post by TeeEm
what seems to be the problem?


I don't understand the logic behind the inequalities formed in the question. I understand the two possible scenarios with the friction acting towards or away from the centre, but I'm not sure how the tension+friction can be greater than the centripetal force, and how the tension-friction can be less than the centripetal force.
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Original post by PhyM23
I don't understand the logic behind the inequalities formed in the question. I understand the two possible scenarios with the friction acting towards or away from the centre, but I'm not sure how the tension+friction can be greater than the centripetal force, and how the tension-friction can be less than the centripetal force.


there is no such thing as the centripetal force
this is a term used by physicists

post the question please
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Original post by TeeEm
there is no such thing as the centripetal force
this is a term used by physicists

post the question please


It's 7b)
IMG_20160215_130906.jpg514.9KB
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Original post by PhyM23
It's 7b)


I will do the question (with different numbers) and post a worked solution by late afternoon for you
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Original post by TeeEm
I will do the question (with different numbers) and post a worked solution by late afternoon for you


Thank you very much
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Original post by PhyM23
Thank you very much


1.jpg
IMG.jpg465.3KB
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Original post by TeeEm
1.jpg


PRSOM

Thanks, much appreciated. Is there a reason you took to be acting outwards? Is this just convention?
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Original post by PhyM23
PRSOM

Thanks, much appreciated. Is there a reason you took to be acting outwards? Is this just convention?


this is the direction of r increasing
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Original post by TeeEm
this is the direction of r increasing


Ahh that makes sense

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