- #1

saadhusayn

- 22

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**Hi,**

My problem is with A.P. French vibrations and waves question 3-10, part (b).

My problem is with A.P. French vibrations and waves question 3-10, part (b).

Question 3-10(a)

A metal rod, 0.5 m long, has a rectangular cross section of area 2 mm2. With the rod

vertical and a mass of 60kg hung from the bottom, there is an extension of 0.25 mm.

What is the Young's modulus ( N/m2) for the material of the rod?

I correctly found the Young modulus.

Part(b) asks:

(b) The rod is firmly clamped at the bottom, and at the top a force F is applied in the y direction [perpendicular to side a, parallel to side b]. The result is a static deflection, y, given by:

y=(4L^3/Yab^3)F

If the force is removed and a mass m, which is much greater than the mass of the rod, is attached to the top end of the rod, what is the ratio of the frequencies of vibration in the y and x directions (i.e., parallel to edges of length b and a)?

Here is a picture of the situation:

https://books.google.com.bd/books?i...as a rectangular cross sectional area&f=false

I don't understand the situation here. If the force that bends the rod is parallel to the y axis, how do the vibrations parallel to the x-axis arise?

Thank you in advance for your help.