# Civil Engineering - Hydraulics - Discussion

### Discussion :: Hydraulics - Section 3 (Q.No.2)

2.

A cylindrical vessel 40 cm high is revolved about its vertical axis so that the water touches the bottom when it just spills out. If the radius of the cylinder is 5 cm, the angular velocity of rotation, is

Explanation:

No answer description available for this question.

 Vaish said: (Nov 16, 2015) (4*g*h/3).

 Abhi said: (Mar 19, 2016) y = yo + [(ω^2 x r^2)/(2 x g)]. 0.4 = 0 + [(ω^2 x r^2)/(2 x g)]. 0.4*2*9.81/0.05 = ω^2. ω = 12.52 rad/sec.

 M.S.Bainsla said: (Dec 25, 2016) 2 rad/sec is correct. I agree.

 Priya said: (May 12, 2017) Please explain it clearly.

 Mrutyunjay said: (May 31, 2017) How? Please explain.

 Arun said: (Aug 21, 2017) How 2rad/sec is correct? Explain.

 Anurag said: (Feb 19, 2018) Explain how.

 Priya said: (Mar 21, 2018) It should be (4/3*g*h).

 Anshu said: (Jun 14, 2018) √ ((0.4*2*9.81)-0.05) = 2.79. Hence answer is A correct.

 Rohit said: (Jul 12, 2018) (4/3 * r * h) * 3.14/180. Putting the values; 4/3 * 40 * 2.23 * 3.14/180. = 2.08 rad/sec.

 Shubham said: (Jul 26, 2018) Formula is. Vessel height =( angula velocity"2 * radius"2)/2g.

 Deepak said: (Nov 6, 2018) According to me, it is 125.28 radian/sec.

 Vasudev said: (Jul 16, 2019) I also got 12.52. Here h equals 40 cm equals omega square x r square which is 5 cm divided by 2x 10 m per sec square.

 Lalit Pathade said: (Oct 17, 2019) Vessel height =( angula velocity^2 * radius^2)/2g. (40) =(angular velocity ^2 * (sqrt(5)) ^2) /(2*9.81). Angular velocity = 2rad/sec.

 Kiran said: (Feb 17, 2020) @ Deepak. You are close to the answer. Just covert the units. 125.28 is in rad/min. Divide by 60 to get 2 rad/sec. 12.28/60 ~ 2 rad/sec.

 Kanya said: (Feb 19, 2020) @Kiran, 12.28÷60 = 0.2 not 2.

 Sunil Padhy said: (May 6, 2020) We know, If a cylinder is rotated with constant angular velocity (v)by the application of external torque. It is called forced vortex motion (V). Or H = (v^2 x R^2 )/(2g). Then v= π{2gH/( R^2)}. To get rad/sec multiple (π/180).

 Slr said: (Dec 1, 2020) Correct ans is 125.28 rad/sec. Equate all in meters for ease. The equation is: H - y(min) = (w^2 x R^2)/(2g) So, here y(min) =0. Therefore 0.4 = (w^2 x .0005)/(2 x 9.81) Solve it, you directly get an answer in rad/sec. There's nothing to convert. After solving. w= 125.28 rad/sec. You need to convert to rad/sec if you get an answer in degree. 180°= π rad/sec 1°= π/180 rad/sec.