Question

(ii) At what speed, will the velocity head of stream of water be equal to 20 cm
ofmercury column? Take g=10 m/s2.
​

Answer 1

Velocity head of Hg column = 20 cm of Hg

Velocity head is given as:

velocity head = h * (13.6 cm of water)

velocity head = 20 * 13.6  cm of water ...(i)

And, velocity head is also given as:

velocity head = v² / 2g

substituing the value of velocity head from eq(i):

20 * 13.6 = v² / 2g

20 * 13.6 = v² / 1000

v = √(20 * 13.6 * 1000)

v = 737.56 cm/sec

or, v = 7.37 m/s

Answer 2

Velocity head of Hg column = 20 cm of

Velocity head is given as:

velocity head = h * (13.6 cm of water)

velocity head = 20 * 13.6  cm of water ...(i)

And, velocity head is also given as:

velocity head = v² / 2g

substituing the value of velocity head from eq(i):

20 * 13.6 = v² / 2g

20 * 13.6 = v² / 1000

v = √(20 * 13.6 * 1000)

v = 737.56 cm/sec

or, v = 7.37 m/s