How Is Acceleration Calculated When a Bureau Starts Moving on a Rough Surface?

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Homework Help Overview

The discussion revolves around calculating the acceleration of a bureau on a rough horizontal surface when a constant horizontal force is applied to initiate its motion. The problem involves concepts of static and kinetic friction, as well as Newton's second law of motion.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the role of static friction in determining the applied force needed to start the bureau moving. There are questions about the transition from static to kinetic friction and how to calculate the applied force using the coefficients of friction.

Discussion Status

Some participants have offered insights into the relationship between static and kinetic friction and how they affect the applied force and acceleration. There appears to be a mix of understanding regarding the methods used to calculate the forces involved, with ongoing clarification needed on the application of these concepts.

Contextual Notes

Participants are navigating the definitions and relationships between static and kinetic friction, as well as the implications of these concepts on the acceleration of the bureau. There is an emphasis on ensuring the correct understanding of force balances in this context.

grouchy
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Homework Statement



A bureau rests on a rough horizontal surface ( mk=0.40, ms=0.50). A constant horizontal force, just sufficient to start the bureau in motion, is then applied.The acceleration of the bureau is:

Homework Equations



F= ma

The Attempt at a Solution



The answer is 0.98 m/s^2 but I'm not sure why. I thought you would only use the kenetic friction since it just starts to move.
 
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You use the static friction to get the applied force. Once it's moving the applied force doesn't change, but now use kinetic friction in your force balance.
 
how can you get the applied force using the coefficient of static friction?..Coefficient of static friction= Fs/Fn
 
pinkyjoshi65 said:
how can you get the applied force using the coefficient of static friction?..Coefficient of static friction= Fs/Fn

Fn=mg. Fs=0.5*mg. To start it moving the applied force must be equal to Fs.
 
ohk..I see..so grouchy's answer is right, although the method is not
 
pinkyjoshi65 said:
ohk..I see..so grouchy's answer is right, although the method is not

He didn't have a method. Hopefully now he does.
 
ok, so you take the fs and subtract the fk? right?
 
Why the question marks? fs is the force pushing the cabinet - fk is the force acting against the push. Use the total force on the cabinet to compute it's acceleration.
 

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