Answer:
The velocity is
![v_2 = 0.96 \ ft/s](https://img.qammunity.org/2021/formulas/physics/college/rhl2atjycei8nlh2ksl0ajvclrbqggxquc.png)
Step-by-step explanation:
From the question we are told that
The initial speed is
![v_1 = 4 \ ft/s](https://img.qammunity.org/2021/formulas/physics/college/gvc2ya0aedctrjuyuxyl5ifdtzjdt41a1h.png)
The cross -sectional area of the first pipe is
![A_1 = 15.7 \ ft](https://img.qammunity.org/2021/formulas/physics/college/w8o9ya0qr28d5yl7ppfpm7fjeyzzkb5kei.png)
The cross -sectional area of the second pipe is
![A_2 = 65.4 \ ft](https://img.qammunity.org/2021/formulas/physics/college/kmfuvfmbsrfhvk2n8inwr5ngo3t8hyto58.png)
Generally from continuity equation we have that
![A_1 * v_1 = A_2 * v_2](https://img.qammunity.org/2021/formulas/physics/college/5kcavnlctwkq5mgafmv5479fzglmyxdjzd.png)
So
![v_2 = (A_1 * v_1 )/(A_2 )](https://img.qammunity.org/2021/formulas/physics/college/3qn5o59cchudscck3kof4i0etpa1z6cftv.png)
=>
![v_2 = (15.7 * 4 )/(65.4 )](https://img.qammunity.org/2021/formulas/physics/college/9rbiksqqs6cv9d14miq8r2cg284f16mfao.png)
=>
![v_2 = 0.96 \ ft/s](https://img.qammunity.org/2021/formulas/physics/college/rhl2atjycei8nlh2ksl0ajvclrbqggxquc.png)