Friction, object at rest then accelerates.

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Homework Help Overview

The problem involves a 2.5 kg block on a 53-degree incline with specified coefficients of friction. The original poster seeks to determine the block's acceleration from an initial state of rest.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relevance of both static and kinetic friction in determining the block's motion. Questions arise regarding whether the block will slide or remain at rest, which influences the choice of friction coefficient.

Discussion Status

Some participants have offered insights into the conditions affecting the block's movement, suggesting that the determination of whether it slides or stays still is crucial for identifying the appropriate friction to use. There appears to be a productive exploration of the problem without a definitive consensus yet.

Contextual Notes

The discussion reflects uncertainty regarding the initial conditions and the implications of the coefficients of friction on the block's motion. The original poster's understanding of the problem setup is still developing.

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Homework Statement



A 2.5 kg block is on a 53 degres incline for which 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?
 
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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.
 
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 which would mean it would slide , which would mean its kinetic only. Well I got it I think. Thank you
 
Last edited:
EvilBunny said:
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 which would mean it would slide , which would mean its kinetic only. Well I got it I think. Thank you
Yes, you have it!
 

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