Coefficent of kinetic friction

AI Thread Summary
The discussion revolves around calculating the minimum coefficient of kinetic friction required for a train to stop safely after colliding with buffers. The scenario involves a train with mass m skidding to a halt due to friction while compressing a spring with spring constant k. The key equations referenced include the work-energy theorem and the relationship between kinetic energy and potential energy stored in the spring. A user expresses confusion about the application of these formulas and seeks guidance on the correct approach. The conversation emphasizes understanding the work done by friction in this context.
spiegalr
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Homework Statement


A train, of mass m, comes into a station traveling slightly too fast to stop in time before it hits the buffers at the end of the track. The buffers are effectively metal plates attached to a spring which obeys Hooke's law with a spring constant k. The trains wheels lock and it skids along the horizontal rails with sparks flying so that at the point that the train first touches the buffers it has a speed v. If the maximum compression of the spring in the buffers is 1m what is the minimum coefficient of kinetic friction between the locked wheels of the train and the rails for the buffers to be able to stop it given that the gravitational field is g?

Homework Equations


W = 1/2kx^2
KE = 1/2mv^2
W = \mumgh

The Attempt at a Solution


I've tried using the Work Energy Theorem like so:
\mumgh - 1/2kx^2 = 0 - 1/2mv^2
But I have no idea what directions to take, or even if I'm using the right formula.
Thanks!
 
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Welcome to PF!

Hi spiegalr! Welcome to PF! :wink:

Hint: what is the work done by the force of friction? :smile:
 
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