A bullet going with speed 350 m/s enters a concrete wall and penetrates a distance of 5 cm before coming to rest.  The deceleration is ……x${10}^{5}m/s$

$\begin{array}{l}\mathrm{given} \mathrm{initial} \mathrm{velocity} =\mathrm{u}=350\mathrm{m}/\mathrm{s};penetration dis\tan ce=\mathrm{s}=5\mathrm{cm}=0.05\mathrm{m}\\ \mathrm{final} \mathrm{velocity}=\mathrm{v}=0\\ \text{ acceleration= }\mathrm{a}=\frac{{\mathrm{v}}^2-{\mathrm{u}}^2}{2\mathrm{s}}=\frac{0-{350}^2}{2\times 0.05}=-12.2\times {10}^5\mathrm{m}/{\mathrm{s}}^2\\ deceleration=12.2\times {10}^5\mathrm{m}/{\mathrm{s}}^2\end{array}$