Question

A bullet emerges from a barrel of length 1.2m with a speed of 640m/s. Assuming constant acceleration ,the approximate time that it spend in the barrel is?

Answer 1

$$\begin{gathered} \mathbf{Acceleration}\mathbf{:} \\ \mathrm{a}=\frac{{\mathrm{v}}^2-{\mathrm{u}}^2}{2\mathrm{s}} \\ =\frac{{640}^2-0}{2\times 1.2} \\ =1.7\times {10}^5\mathrm{m}/{\mathrm{s}}^2 \\ \mathbf{Time}\mathbf{}\mathbf{interval}\mathbf{:} \\ \mathrm{t}=\frac{\mathrm{v}-\mathrm{u}}{\mathrm{a}} \\ =\frac{640-0}{1.7\times {10}^5} \\ \mathbf{=}\mathbf{3}\mathbf{.}\mathbf{75}\mathbf{\times }{\mathbf{10}}^{\mathbf{-}\mathbf{3}\mathbf{}}\mathbf{s}\mathbf{}\mathbf{\left(}\mathbf{or}\mathbf{\right)}\mathbf{}\mathbf{3}\mathbf{.}\mathbf{75}\mathbf{}\mathbf{milli}\mathbf{}\mathbf{seconds} \end{gathered}$$