The aluminum strut is 10 mm thick and has the cross section...

Transcript

00:01 In this problem, let us first look at the cross section.

00:25 We are given this length as 10.

00:36 This has also 10.

00:38 This is given as 40.

00:43 Also, we have this as 30 and this as another 10.

00:52 Also, this is 30.

00:54 And this is next, we have this center region as 40.

01:04 Everything is given an mm this is b and this is a now first we will find y bar which is the centroid of this cross section for that y bar will be somewhere this distance from the base will be y bar this first calculate y bar for y bar we will first take that this divided into few areas this be area one this be similarly like that next is these two and the this is two this is two this is one and this is three so for one it is two times center of gravity of one will be at five minutes zero point 0 .005 into its area which is 0 .03 multiplied by 0 .01 plus for 2 it is twice of area first which is 0 .06 into 0 .01 into its center of gravity for 2 will lie at since it is at height 3 half of this will be 0 .03 plus plus for 3 the center of gravity will lie here at its center and this will be 0 .055 into its area which is 0 .04 by 0 .01 whole divided by the areas which is 2 times 0 .03 into 0 .01 plus twice of 0 .06 into 0 .01 plus 2 .06 into 0 .01 plus 0 .01 plus 0 .0 .6.

03:27 0 .04 into 0 .01.

03:31 Here i use the fact that y bar is simply y of each part into its area by summation of area.

03:42 This comes as 0 .077 meters.

03:58 Next let us find its area moment of inertia...