Stress and Strain Factor of Safety

[nettie2311]

Homework Statement

Hello,

I've been given a question:

The ultimate strength of a round steel rod is 560MPa. If a factor of safety is 6 is required, what is the maximum permissible load for the rod if it has a diameter of 6.9cm?

If anyone can explain how to set up this calculation and how I go about solving this question it would be great.

 

[nettie2311]

Homework Statement

Hello,

I have been given the question:

What is the factor of safety of a steel hanger having an ultimate strength of 560MPa and supporting a load of 71000N. The steel hanger in question has a cross sectional area of 5 cm squared.

If anyone can help me set up the formula and explain how I go about solving this question that would be great.

 

[nettie2311]

Hello,

Thanks for the reply...I've tried calculating it and I'm pretty close but for some reason a few decimal places off.

I'm guessing I need to convert cm squared to metre squared? And MPa to Pa? I'm getting all confused.

 

[rock.freak667]

Start with the definition of the factor of safety, how does it relate the maximum stress to the ultimate stress?