Question

(b) Determine the moment of inertia about y axis for the section shown in Figure Q3(b). (10 marks) 1 All dimensions in m.

Find the Value of ( Y par ). And find moment of inertia about Y - Axis .

Answer 1

Calculation...

Given us on 3 $ 3 *tt • Calculation for y ou • pirst we divide the section into 3-small Rectangular - section. Named as 0 , ③ (we do this because centroid and moment of Inertia of rectangular section is easy for Calculation) - Calculation → area of ① = A, l a 4x1= 4 m² - Controid of 0 from xe- amis = y = 4 = 2m - area ob ② = A₂ = (3+3)x1 = 6 m² @ cerdooid of ♡ = y = + = o.sm . @ area of ③ = Az = 4x1 = 4m² centroid of 6 = Y3 = 14 / 2 = 2m

Then } i A Y3 J. 2014 mart Any + A₂Yzt AITA₂+ A3 t ux2 4x2 + 6x0.5 4+6+4 Tj = 1.3571 m) Answer . Now we make Calculation fout moment of inertia of scect section about gaxis. perpendiculare axis Note: In this calculation we use thearm. moment Moment of inertia a inertia about y-dois Monsent of I moment] inertia of 1 of absoarea tinertia about yaxus area of I dream Ig: 3, + 3, + 1, I, + 12 + 13

- X1 X 4 Suvirct wylusy + boxixu?+ 1x4x7.5" u + 1x4X 7.5:9 12 Jy= 333.1667 mt 3-3031667 m Required for den