A thin rod AB of uniform cross sectional area is suspended from end A. If x be the elongation of the rod, then
elongation of the lower half is x/2
elongation of the upper half is x/2
elongation of the upper half is 3x4
elongation of the lower half is x/8
x=mgl/2AY=mgl2AY
x1=Elongation of AC=mg/2l/4AY+mg/2l/2AY
⇒x1=3mgl8AY=3x4
x2=Elongation of the lower half CB=mg2x4AY=mgl8AY=x4