$13$

Formula $10$ points

A beam has the symmetrical cross section given below. The centroid is at the axes origin and all values are in mm$.$ The thickness of the top part is $1\mathrm{.}3$ mm and the thickness of all other parts is $0\mathrm{.}8$ mm $.$

The values of second moment of area are:

$I_x=340\mathrm{.}8{10}^{3}m{m}^4,I_y=81{10}^{3}m{m}^4,I_{xy}=0$

A shear force $S_y$ of $2,687N$ is applied as shown. There are no other forces acting on the section.

What is the maximum shear stress in the section?

Enter your answer as a positive number $($ie ignore the sign$)$ in units of $Nm{m}^{-2},$ but don't include the units. You have a $3\%$ margin of error.