A liquid of densilty 1200 kg//m^(3) flowing steadily in a tube of varying cross section. The cross section at a ponit A is 1.0cm^(2) and that at B is 20mm^(2), the ponts A and B are in the same horizontal plane. The speed of the liquid at A is 10cm/s. Calculate the difference i pressure at A and B.

A liquid of densilty 1200 kg//m^(3) flowing steadily in a tube of vary

1.	A liquid of densilty 1200 kg//m^(3) flowing steadily in a tube of varying cross section. The cross section at a ponit A is 1.0cm^(2) and that at B is 20mm^(2), the ponts A and B are in the same horizontal plane. The speed of the liquid at A is 10cm/s. Calculate the difference i pressure at A and B.
Answer» Solution :From equationof continuity, the speed `v_(2)` at B is given by `A_(1)v_(1)=A_(2)v_(2)` or `(1.0)^(2)(10)=(20xx10^(-2))v_(2)` or `v_(2)=1.0/(20xx10^(-2))xx10=50`cm/s Ber Bernoull.s equation `P_(1)+rhogh_(1)+1/2rhov_(1)^(2)+P_(2)+RHO gh_(2)+1/2rhov_(2)^(2)` Here `h_(1)=h_(2)` Thus `P_(1)-P_(2)=1/2 rho v_(2)^(2)-1/2rhov_(1)^(2)` br> `=12XX(1200)(2500-100)` `=600xx2400=144` Pa