ASsume teh z axis is the vertical axis(adsbygoogle = window.adsbygoogle || []).push({});

A homogenous rope of mass M and length L hangs vertically from a point of hte ceiling.

Find the magnitude of the force F(z) by which the top part of the rope acts on teh lower segment of the rop at the distance z from the free end of the rope.

Not quite sure here Would i have to use something like mass density of each segment like how you do for a line of charge calculation??

so then define [tex] \lambda = \frac{M}{L} [/tex]

so then [tex] F(z) = m_{eff} g [/tex]

[tex] F(z) = \lambda z g = \frac{Mg}{L} z [/tex]

good so far??

Now the rope is spun in a horizontal circle with constant angular velocity omega. Ignore gravity.

Find the magnitude of the force F(r) by which the inner part of the rope acts on the outer segment of the rope at the distance r from the center of the circular motion.

so use the same lambda as before

The question above has been copied from teh book verbatim. I'm wondering if the rope is being spun about its center or from one end?

[tex] F(r) = m_[eff} \omega^2 r [/tex]

[tex] F(r} = \lambda r \omega^2 r = \frac{M}{L} \omega^2 r^2 [/tex]

now i know this is wrong becuase th book gives the answer to be [tex] F(r) = \frac{M \omega^2}{2L} (L^2 - r^2) [/tex]

where di i go wrong??

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# Homework Help: Rope hanging from teh ceiling

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