Friction, object at rest then accelerates.

In summary, the problem involves a 2.5 kg block on a 53 degree incline with Uk = 0.25 and Us = 0.5. It is initially at rest and the question is asking for its acceleration. The key is to determine whether it will start to slide or remain at rest, and use the appropriate friction coefficient for the calculation.
  • #1
EvilBunny
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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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  • #2
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.
 
  • #3
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
 
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  • #4
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!
 

FAQ: Friction, object at rest then accelerates.

What is friction?

Friction is a force that resists the motion of an object as it moves along a surface or through a fluid. It is caused by the interaction between the surfaces of two objects in contact.

How does friction affect an object at rest?

When an object is at rest, friction prevents it from moving by creating resistance against any external forces acting on it. This is known as static friction.

What happens when an object at rest starts to accelerate?

As the object starts to accelerate, the force of friction changes from static to kinetic friction. Kinetic friction is the resistance to motion when an object is already in motion. This force acts in the opposite direction of the object's motion, slowing it down.

What factors affect the amount of friction experienced by an object?

The amount of friction experienced by an object depends on several factors, including the roughness of the surfaces in contact, the force pressing the surfaces together, and the type of material the surfaces are made of.

How can friction be reduced in order to increase the acceleration of an object?

Friction can be reduced by using lubricants, smoothing or polishing the surfaces in contact, or reducing the force pressing the surfaces together. By reducing friction, the object will experience less resistance and can accelerate more easily.

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