When a smooth-flowing stream of water comes out of a faucet, it narrows as it falls. Explain.

Solution 29DQ Introduction We have to discuss why the cross section decreases as the water flows down from the faucet in steady state flow. Step 1 From the continuity equation we can write that A1 1= A 2 2 Av = constant 1 A v That is for steady streamline flow the cross sectional area is inversely proportional to speed of the fluid. That is if the speed increases the cross sectional area decreases. Now, when water comes down from the faucet, the water is actually freely falling under the gravity, hence the speed of the water will increases. Since the speed increases, the area of cross section will decrease. That is why the water becomes narrow as it comes down from the faucet.