Chapter 2, Problem 2.80HP

Refer to Figure P2.79 but assume that the cantilevered beam loaded by a force F is made of steel. Strain gauges $R_1,R_2,R_3,$ and $R_4$ are attached to the beam and connected in the circuit shown. The force causes a tension stress on the top of the beam that causes the length (and therefore the resistance) of $R_1$ and $R_4$ to increase and a compression stress on the bottom of the beam that causes the length (and therefore the resistance) of $R_2$ and $R_3$ to decrease. The result is a voltage $v_{BA}$ across nodes B and A.Determine this voltage if $F=1.3\text{MN}$ and
$\begin{array}{l}{R}_{\sigma }=1\text{k}\Omega v_s=24VL=1.7\text{m}\\ w=3\text{mm}h=7\text{cm}Y=200{\text{GN/m}}^2\end{array}$