# Homework Help: Stress, Shear and other things?

1. Jul 9, 2010

### darrenfiander

1. The problem statement, all variables and given/known data

We've been given several questions and told to use the internet to find out the formulas for them. But I can not find the right ones anywhere!

If anyone could just give the formulas thats all I need!

A seat is attached by a simple pin of a circular cross section, made from a material with an allowable strength in shear of 100MPa what would be the minimum diameter to withstand a mass of upto 100kg? pin can only penetrate one side

A straight, hollow circular setion post having an outside diamter of 100m and a thickness of 2mm is to be rigidly fixed to the floor at its base to support an object. calculate the second moment of inertia

if the canister is made of aluminium having a youngs modulus of 70gpa and possion ratio of 0.28, calculate the resultant axial and hoop strain it will experience

2. Relevant equations

3. The attempt at a solution

2. Jul 9, 2010

### pongo38

To start you off, you probably know that stress=Force/area. There are two types of stress: normal stress and shear stress. Normal stress is force /area perpendicular to the force. Shear stress is force/area parallel to the force. However, all that needs interpreting in the questions you have been given. I think you need to submit your interpretation before getting more help. The moment of inertia is sometimes termed second moment of area (even though they are conceptually slightly different, it may help you get to where you want to be....