- #1

jasonbot

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## Homework Statement

I have to find the Shear Force and Bending Moment diagrams for this problem. The lengths in the picture are 1.2m each and the peak force is 4kN/m and I calculated the support reactions to be:

Ay=4,8kN (up)

Ma= 5.76kN.m (anticlockwise)

## Homework Equations

These are what I'm looking for but failed to do...

## The Attempt at a Solution

I first section the beam 0<x<4Efy=0

+4.8 -.5x*3.33x-Vx=0

I got the 3.33x by using similar triangles; if triangle 1 is (1,2;4) then sectioned triangle should be (x;y) so therefore 4/1.2=y/x x=3.33xthis gave me Vx=-1.67x^3+4.8 which is wrong.

Then EMo=0

+Mx +.5x*3.33x*(x/3) -4.8x +5.76=0

which gets me Mx=-0.56x^3 +4.8x +5.76The correct answers for this question are:

Vx=4.8 -(x^3/6)

Mx=4.8x -(x^3/18) -5.76I have a feeling I'm not using the triangle force correctly. Please advise.