Finding a max load from the yield stress

[Lap9387]

1. Homework Statement I have a bar, 500mm long (0.05m) 10mm wide (0.01m) and 3mm deep (0.003 m)The bat has a load applied in the centre of 30nI know the maximum yield stress is 150 mpa 150x10^6How do I calculate the maximum load the bar can take?2. Homework Equations I used stress = m y / I3. The Attempt at a Solution I calculated the bending moment to be 3.75 at 250mm (.25m) using a shear bending diagram,*I then reversed the equation above to get:150x10^6 = 0.0015m/2.25x10^-11Which gives m as : (150x10^6 x 2.25x10^-11) / 0.0015M = 2.25I know the bending moment is at .25 mSo divide 2.25 / .25I get 9The answer can't be 9n as the question uses 30nCan someone please show me how to solve this?.Thanks in advance x*

 

[Vadar2012]

You missed the most important point. How is the bar supported?

 

[Lap9387]

Sorry, the bar is simply supported at either end