CGPET 2019 Solved Paper

First of all we divide the rod into 2 parts of lengths

2L

3

and

L

3

and where force F is acting.
Case I Force acting on both side of

2L

3

is 3F.
So, elongation x1 will be
x1=

[3F× 2L 3 ]

AY

.......(i)
Case II Force acting on both side of

L

3

is 2F.
So, elongation x2 will be
x2=

[2F× L 3 ]

AY

........(ii)
Now, total elongation, x=x1+x2
=

(3F× 2L 3 )

AY

+

(2F× L 3 )

AY

x=

8 3 FL

AY

=

8FL

3AY