# I Isn't the force calculated twice?

Tags:
1. Oct 17, 2016

### arpon

Isn't the force calculated twice here? For example, the force along AB is at first calculated for the resultant force along OB, then for the resultant force along AC.
I think the compression and tensile stress should be $\frac{F}{2a}$.

2. Oct 18, 2016

### haruspex

Forget that it is a solid block for the moment and think of it as a framework of rods. The vertex A is subject to tension F along AB and tension F along AD. The resultant is a force F√2 along AO.