The average velocity $v$ of flow of clear water in a $100\; cm$ (inner) diameter tube is measured using the ultrasonic flow meter as shown in the figure. The angle $\theta$ is $45^\circ$. The measured transit times are $t_1 = 0.9950\;ms$ and $t_2 = 1.0000\; ms$. The velocity $v$ (in m/s) in the pipe is (up to one decimal place) $\_\_\_\_\_$.
