Assume that the largest stone of mass $m$ that can be moved by a flowing river depends upon the velocity of flow $v$, the density $d$ and the acceleration due to gravity $g$. If $m$ varies as the $k^{\mathrm{th}}$ power of acceleration due to gravity, then find the value of $\left|2k\right|$.

In the figure shown $S_1$ and $S_2$ are two identical coherent sources of sound, separated by d. A receiver moves along line $XY$ which is parallel to $S_1{ S}_2$ to detect intensity of sound at various points on the line. Distance of line $XY$ from $S_1{ S}_2$ is $D\left(>>d\right).$ Distance of first intensity maxima on line $XY$ measured from $O$ is $\mathrm{y}.$ Find percentage change in value of $y$ if the temperature of air increases by $1\%.$ If your answer is $X\%$ fill value of $6X.$