Water flows through a horizontal tube of variable cross section as shown in the figure. The area of cross section at A and B are 4 mm2 and 2 mm2 respectively.  If 1 cc of water enters per second through A , find (a) the speed of water at A (b) the speed of water at B and (c) the pressure difference PA  - PB

 

Suppose the tube in the previous problem is kept vertical with A upward but the other conditions remain the same. The separation between the cross sections at A and B is 15/16 cm. Find (a) the speed of water at A (b) the speed of water at B (c) the pressure difference PA  - PB. . Take g = 10 m s-2

 

Suppose the tube in the previous problem is kept vertical with B upward . Water enters  through B at the rate of 1 cm3 s-1 . Find (a) the speed of water at A (b) the speed of water at B (c) the pressure difference PA   - PB. Note that the speed decreases as the water falls down

Asked by Paresh | 2nd Jan, 2016, 08:51: PM

Expert Answer:

 
If the tube is kept vertical with B at the top, then the speed of water entering the tube will be 0.5 m/s and the speed of water at A will be 0.25 m/s.
The pressure difference between the ends remains zero. 

Answered by Yashvanti Jain | 5th Jan, 2016, 11:59: AM