Question

Water enters a horizontal pipe with a rectangular cross section at a speed of 1.00 m/s. The width of the pipe remains constant but the height decreases. 27.3 m from the entrance, the height is half of what it is at the entrance. If the water pressure at the entrance is 2921 Pa, what is the pressure 27.3 m downstream?

Answer 1

use the law of continuity to figure the speed downstram

speeddownstream=speedupstream*areaupstream/areadownstream

where area means cross sectional area.

Now, use Bernoulli's law to figure pressure downstream http://www.4physics.com/phy_demo/Bernoulli/Bernoulli.html

because heights are the same (horizontal), it reduces to

P1 + d*v1^2=P2+ d v2^2

solve for P2

Answer 2

I can not find the value of v^2