- #1

sagarbhathwar

- 29

- 0

## Homework Statement

[/B]

Determine the rectangular and polar radii of gyration of the shaded area about the axes shown.

## Homework Equations

dI

_{x}= y

^{2}dA

I

_{x}= ∫y

^{2}dA

dA = ydx

A = ∫(dA

## The Attempt at a Solution

dI

_{x}= y

^{2}dA

=(x

^{6}/16) *(x

^{3}/4) dx

=(x

^{9}/64)dx

I

_{x}=(integrating from 1 to 2) ∫dI

_{x}= 1023/640

dA = ydx

A = (integrating from1 to 2)∫(x

^{3}/4)dx = 15/16

k

_{x}= √(I

_{x}/A) = 1.705

I am getting the radius of gyration about y-axis correctly but that baout x-axis is wrong.

The actualy answer given is 0.75. I am unable to figure out where I am going wrong.