The internal shear force at a certain section of a steel beam is $V=220kN.$ The beam cross section shown in the figure has

dimensions of $t_f=18mm,b_f=310mm,d=390mm,$ and $t_w=14mm.$ Determine:

$($a$)$ the shear stress at point $A,$ which is located at $y_A=72mm$ below the centroid of the wide$-$flange shape.

$($b$)$ the maximum horizontal shear stress in the wide$-$flange shape.

Below, enter the magnitudes of the shear stresses, so enter positive values for both answers.

$($a$){}_A=$

MPa

$($b$){}_{\text{m}\text{a}\text{x}}=$

MPa