Recent content by cigarette

Actually i am writing a program to provide the user with the geometrical properties of a section. The section is approximated by straight lines and all vertices are known. With regards to symmetry, i assume none, cos the section is "arbitrary". I aim to provide the user with the area...

Hi tide, i don't quite get it. So let's say i have a planar region (2D) with vertices known, does it suffice if i find the moments of inertia about the origin for the section of interest? If i find the moments about the origin, does it make a difference if i find it about the centroid of the...

Hi all, Why are there so many moments of inertia for a given section? That is, i come across moments about the origin, x-axis, y-axis, centroid, xy-axis...etc... What are the differences? are there typical applications? Please point me in the correct direction Thanks in advance, any...

hi bartholomew, thanks for reply. i understand how the triangles work, but am just wondering whether there is any other mathematical method suitable for this operation? regards

hi tide, in response to ur question, it is an arbitrarily shaped polygon, which basically means any shape with any number of vertices..maybe can call it "n"-agon. i get the triangular part, but just wondering whether there is any other mathematical methods. regards

How can one calculate the moment of inertia of a polygon? Assuming that one knows the polygon’s total area, centroid and vertices, which are connected by straight lines in a 2D system. Is it possible to avoid a difficult integral over the area/mass? Any helpful information is highly...

Hi Ivy and Bartholomew, thanks for replies. I actually used Green's theorem in a Plane to work the centroid out. The formula is CentreX = {Sum[(Xsubi + Xsubi+1)X(Xsubi*Ysubi+1-Xsubi+1*Ysubi)]}/6A, where sub means subscript, A means Area and X and Y are the X-Y co-ordinates respectively. (i...

Green's Theorem-->Does it work for ..? Hi all, i am interested in finding out the Geometrical properties of an arbitrary section, which means 2D area. Rather than having to perform manual calculations everytime, i am trying to write a program to help me with this. There is a problem however. I...

Hi all, i am interested in finding out the Geometrical properties of an arbitrary section, which means 2D area. Rather than having to perform manual calculations everytime, i am trying to write a program to help me with this. There is a problem however. I cannot seem to find the appropriate...