Question #8ae4b

1 Answer
Mar 25, 2017

Drawn

Given that an ideal fluid flows in the tube as shown figure.

The pressure of the fluid at the bottom (P_2)(P2) is equal to the pressure of the fluid at the top (P_1)(P1) i.e. (P_1=P_2)(P1=P2) )

The difference in height of the top and bottom h_1-h_2=3mh1h2=3m

The velocity of the fluid at the top v_1=2m"/"sv1=2m/s

The velocity of the fluid at the bottom v_2="unknown"v2=unknown

The area of cross-section of the pipe at the top A_1A1

The area of cross-section of the pipe at the bottom A_2A2

We are to find out the ratio of A_1:A_2A1:A2

Now applying Bernoulli principle

"Energy per unit volume at the top"= "Energy per unit volume at the bottom"Energy per unit volume at the top=Energy per unit volume at the bottom

we have the following equation

P_1+1/2rhov_1^2+rhogh_1=P_2+1/2rhov_2^2+rhogh_2P1+12ρv21+ρgh1=P2+12ρv22+ρgh2

where

rho= "density of the fluid"ρ=density of the fluid

and g = "acceleration due to pop gravity"=10m"/"s^2 andg=acceleration due to pop gravity=10m/s2

Inserting given values in the above equation we get

cancelP_2+1/2cancelrho2^2+cancelrho10h_1=cancelP_2+1/2cancelrhov_2^2+cancelrho10h_2

=>2+10h_1=1/2v_2^2+10h_2

=>2+10h_1-10h_2=1/2v_2^2

=>2+10(h_1-h_2)=1/2v_2^2

=>2+10xx3=1/2v_2^2

=>v_2^2=64

=>v_2=sqrt64=8m"/"s

Now applying principle of continuity of flow of ideal fluid we can write

A_1/A_2=v_2/v_1=(8m"/"s)/(2m"/"s)=4/1 which is option (2)