Problem $3$: A cylindrical pressure vessel is fabricated by butt$-$welding $20-$mm thick plate with a spiral seam as

shown in the figure below. The pressure in the tank is $2800$ kPa $,$ and an axial load of $130$ kN is applied to the end

of the tank through a rigid bearing plate. Determine:

The normal stress perpendicular to the weld.

The shearing stress parallel to the weld.

The maximum shearing stress at a point on the outside surface of the vessel

maximum shearing stress at a point on the inside surface of the vessel.