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Water is flowing smoothly through a closed pipesystem. At one point A, the speed of the water is 3.0 m s^(-1)while at another point B, 1.0 m higher, the speed is 4.0 m s^(-1) . The pressure at A is 20 kPa when the water is flowing and 18 kPa when the water flow stops. Then |
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Answer» the pressure at B when water is flowing is 6.7 KPA. `P_1 + rho gh_1 + 1/2 rho v_1^2 = P_2 + rhogh_2 + 1/2 rho v_2^2`….(i) Putting `v_1=30 m s^(-1) , v_2=4.0 m s^(-1) , (h_2-h_1) = 1M , P_1`= 20 kPa we get , `P_2=20+ [ 10^3 xx 9.8 (-1)+ 10^3/2 [ 9-16]]` =20-9.8-3.5 =6.7 kPa Also when the flow stops , `v_1=v_2=0` and then from (i) , `P._2`=18-9.8 = 8.2 kPa |
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