Heavy Duty Trolley Plastic Bending & Strain Energy

[Liquito]

Homework Statement

http://imgur.com/a/RoKVR

The link above have the full problem
I mostly have issue with Part (b) of the problem where am not familiar with and don't know how to solve that part. I was wondering if someone can put some light in the tunnel or provide a link where I can study about this type of problems

As for Part (a) I attempted it and although came really close to the solution is not what am asked to prove so I was wondering if someone can spot any problem with my calculation there

Homework Equations

M = P*L1 = P*R*sinθ
T = P*L2 = P*R*(1-cosθ)

The Attempt at a Solution

This is my attemp and what method I used for it

http://imgur.com/a/oXpPG

 

[Nidum]

M = P*L1 = P*R*sinθ
T = P*L2 = P*R*(1-cosθ)

Show me how you derived the expression for T .

 

[Liquito]

Show me how you derived the expression for T .

I am not sure I understood correctly what you are looking for but I included both what T is = to and its derived version