GATE2016-1-34

Question

A simply-supported beam of length $3L$ is subjected to the loading shown in the figure.

It is given that $P=1\: N$, $L=1\:m$ and Young’s modulus $E=200\:GPa$. The cross-section is a square with dimension $10\:mm\times10\:mm$. The bending stress (in $Pa$) at the point A located at the top surface of the beam at a distance of $1.5L$ from the left end is _____________
(Indicate compressive stress by a negative sign and tensile stress by a positive sign.)