A steel  (E = 200 GPa,v = 0.29) bar of diameter 17 mm is subjected to a torque 2.1 kNm and a tensile axial load of 16 kN as shown in the figure below. 

Two strain gauges (K = 2.0) are bonded to the bar in the Poisson configuration and connected into a Wheatstone half-bridge configuration using arms 1 and 2, as indicated.

The bridge input voltage is 9 V.

3.1. Calculate the output voltage.