Answer
850810 Nm
Work Step by Step
We can write the torque that the plunger creates about the axis shown in the figure,
$\tau=Fl=PAl$ ; Let's plug known values into this equation.
$\tau=(35.4-1.01)10^{5}N/m^{2}\times\pi(0.15\space m)^{2}(3.5\space m)=850810\space Nm$
