- #1
TheSodesa
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Homework Statement
A platform (m = 5,0kg) is suspended from 4 steel cables whose length is 3,0m and diameter 2mm.
a) How much further will the platform sink if a mass of 50kg is placed on the platform?
b) What is the maximum load that the wires can hold before breaking?
Homework Equations
[tex]\dfrac{\Delta F}{A} = E\dfrac{\Delta L}{L}[/tex]
The Attempt at a Solution
Part A was easy enough; simply assume that the wires remain in the elastic zone of deformation and that A doesn't change much and plug in the values. However part B baffles me, and I'm not sure where to start.
Surely the cross sectional area A doesn't go to zero as the cable breaks(division by zero)? Am I supposed to use calculus to figure out when E changes(doesn't really make sense since E is a constant for elastic situations)? How would I even do that? Does steel have documented values for when a wire of certain L and A starts deforming plastically? I couldn't find any.
I don't have the right answers for this problem, so I can't just try one of the above methods to find out if it was the correct one, not that any of them make any sense to me. If someone could point me in the right direction, that would be great.