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Friction, object at rest then accelerates.

  • Thread starter EvilBunny
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  • #1
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1. Homework Statement

A 2.5 kg block is on a 53 degres incline for wich Uk = 0.25 and Us = 0.5 . Find its acceleration given that (a) it is initially at rest.



I don't know how to approach this. We have kinetic friction when an object slides. This object starts at rest. Does that mean that we will have both kinds of friction in this problem?
 

Answers and Replies

  • #2
PhanthomJay
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It's initially at rest because it is being held there or placed there. As soon as it is released from rest, it will either start to slide, or remain at rest. Can you determine which is the case? It's one or the other, and depending on whether it moves or stays still, that's the value of the friction coefficient you should use.
 
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Well I'd go with kinetic friction. As its asking me to find the acceleration , but it could be possible its 0 so I could verify if the force on the block is bigger then Fs wich would mean it would slide , wich would mean its kinetic only. Well I got it I think. Thank you
 
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  • #4
PhanthomJay
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Well I'd go with kinetic friction. As its asking me to find the acceleration , but it could be possible its 0 so I could verify if the force on the block is bigger then Fs wich would mean it would slide , wich would mean its kinetic only. Well I got it I think. Thank you
Yes, you have it!
 

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