Two bars connected by a spring on a floor with friction

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The discussion revolves around a physics problem involving two blocks connected by a spring on a frictional surface. Participants analyze the forces acting on each block and the role of friction, seeking to determine the minimum force required to move the first block, m1. Key equations are established, including those for force and energy, while participants debate the significance of acceleration and equilibrium in the context of the spring's behavior. Ultimately, the solution converges on the relationship between the applied force, friction, and the spring constant, leading to the conclusion that the minimum force can be expressed as F = μ(m1g/2 + m2g). The conversation emphasizes the importance of free body diagrams and understanding the dynamics of the system.
  • #31
PeroK said:
You need to think about what happens after the equilibrium point.
Is this the equation we should be concerned with?
##Fx - μm_2gx - 1/2kx^2 = -1/2m_2v^2##
 
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  • #32
Null_Void said:
Is this the equation we should be concerned with?
##Fx - μm_2gx - 1/2kx^2 = -1/2m_2v^2##
No. That's no use, as you yourself have repeatedly complained about the ##v^2## term being a nuisance.
 
  • #33
PeroK said:
No. That's no use, as you yourself have repeatedly complained about the ##v^2## term being a nuisance.
Will it perform simple harmonic motion about the equilibrium point?
 
  • #34
Null_Void said:
Will it perform simple harmonic motion about the equilibrium point?
No.
 
  • #35
Null_Void said:
But an extra velocity term ##v## is still present? What value should ##v## take in this case
Suppose there is still a velocity term at that point. What would happen if you were to make F just a tiny bit less?
 
  • #36
PeroK said:
No.
## Fx - 1/2kx^2 - μm_2gx= 0##
Is this the right equation?
 
  • #37
Null_Void said:
## Fx - 1/2kx^2 - μm_2gx= 0##
Is this the right equation?
It is. It's useful because that's the point at which ##m_2## stops. And that's the point at which the force in the spring is at its maximum.
 
  • #38
PeroK said:
It is. It's useful because that's the point at which ##m_2## stops. And that's the point at which the force in the spring is at its maximum.
Ah I get it now. Combining this with the equation @haruspex pointed out, I'll get
##F = μ(m_1g/2 + m_2g)## which is the correct answer, Thanks for your help everyone!
 

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