$($Problem $6-71$ modified$)$ The man has a mass of $78$ kg and stands motionless at the end of the diving board. The board has a rectangular cross section $20$ mm high by $350$ mm wide. The maximum moment is $1,912\mathrm{.}95Nm$ and the maximum shear force is $2040\mathrm{.}48$ N $($can you confirm this using statics?$)$

a$.$ Determine the maximum normal strain developed in the board. The modulus of elasticity for the material is $E=125$GPa. Assume $A$ is a pin and $B$ is a roller. $($Hint: Find the normal stress and use Hooke's Law$).$

b$.$ Determine the maximum shear stress developed in the board.