00:01
Hello students, here the given triangles are isosceles and we have to calculate the 4's in members bc that is this one, be and bf.
00:13
In this case as it is isosceles all this that is ag, af, bf, be, ce and cb.
00:22
So all are equal and let this be equal to x.
00:29
That is ag equal to af equal to bf equal to be equal to ce equal to cb equal to x.
00:44
And let's draw a perpendicular from this that is this is a prime and from f let's draw a perpendicular this is f prime and again if we draw a perpendicular from e this is e prime.
01:03
Now all this angles are 63 degrees and here that is the load is acting and from the triangle that is this triangle we can write that sin 63 degree is equal to aa prime divided by ag.
01:29
So we get aa prime is equal to x into sin 63 degree and next is aa prime, ff prime and ee prime.
01:43
All this are equal so therefore aa prime, ff prime and ee prime all are equal to equal and this is equal to x sin 63.
02:02
Since we have calculated the value of aa prime.
02:06
Then next is gf so that is this distance and fe and ed all this distance are equal that is gf equal to fe equal to ed.
02:22
So that will be equal to 2x cos 63 degrees.
02:28
Now let's calculate the force in the member bc that is this one.
02:33
So for this let's cut the section like this.
02:42
So let this be 1 and after cutting this we have to take the moment about e.
02:50
Now if we take this we get the expression minus f of bc into ee prime plus l into ed...