Velocity as a function of length

AI Thread Summary
The discussion revolves around calculating the velocity of a falling chain as a function of its remaining length. Participants debate whether the mass of the chain is relevant to the problem, concluding it does not affect the outcome. The conversation shifts to the appropriate equations for solving the problem, with suggestions to use conservation of energy instead of classical equations due to the variable mass of the chain during its fall. There is confusion regarding the applicability of constant acceleration equations in this scenario, as the mass of the chain changes continuously. Ultimately, the consensus leans towards using energy conservation principles to derive the solution.
Tombo254
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Homework Statement



A uniform chain of length 3 metres and mass 6 kilograms is held by one end so that the other end
just touches the floor. If the chain is released, find its velocity as a function of the length of chain
still falling. How fast does the end of the chain hit the floor?

Homework Equations





The Attempt at a Solution



Does the mass of the chain even matter, or is it a distraction? This is for a calculus based physics course, but I think it can be solved using classical equations, ie: v=xt+1/2at2.
 
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Hi Tombo254! Welcome to PF! :smile:

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Tombo254 said:
Does the mass of the chain even matter, or is it a distraction?

you're right, it doesn't matter! :smile:
… I think it can be solved using classical equations, ie: v=xt+1/2at2.

mmm … that's only for constant acceleration …

i think you'd better use conservation of energy :wink:​
 


tiny-tim said:
mmm … that's only for constant acceleration …

I'm confused ... the chain is falling under the effect of gravity, right? ... which is constant.:confused:

isnt it because the mass of chain in free fall changes continuously and thus v = u + at is not valid ? :confused:
 

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