Physical Mathematics Problem: A three-story building with a reservoir on the third floor and four outlets on the first floor (13.3MM), with a height difference of 6m. How long does it take to discharge 200L of water? The inner diameter of 4 branch pipes should be 12.5mm, so the area: S=πr? = 122.7(mm？ )=0.0 1227(dm？ )

According to the law of free fall, the velocity of water is:

v？ =2gh=2x 10x6= 120

V= 10.954 (m/s) = 109.44 (decimeter/s)

It is known that the effluent volume per second is v*s= 1.34(dm? ) = 1.34 (length)

Yes, it needs t=200/ 1.34= 149(s).