Question

 

Find out the velocity of efflux of water from a hole in the wall of a tank made at 20 m below the free surface of water in the tank.

g = 10 m/s2.

Solution

Correct option is

20 ms–1

 

The velocity of efflux of water the hole is  

          

where h is the depth of hole from the free surface of water. Here h = 20 m.   

     

               = 20 ms–1.

SIMILAR QUESTIONS

Q1

An air bubble of radius 0.1 mm is moving upwards in water with a velocity of 0.35 cm/s. If the density of water is  and gravitational acceleration is 9.8 m/s2 and the density of the air is negligible, then find out the coefficient of viscosity of water.     

Q2

A small sphere falls from rest under gravity in a viscous medium, producing heat due to friction. Find how rate of production of heat does depend upon the radius of the sphere at terminal velocity.

Q3

Water at a pressure of  flows at 2.0 m/s through a pipe of 0.02 m2 cross-sectional area which reduces to 0.01 m2. What is the pressure in the smaller in the cross-section of the pipe?

Q4

Water is flowing through two horizontal pipes of different diameters which are connected together. In the first pipe the speed of water is 4.0 m/s and the pressure is . Calculate the speed and pressure of water in the second pipe. The diameters of the pipes are 3.0 cm and 6.0 cm respectively.

Q5

A liquid is kept in a cylindrical vessel which is being rotated about its axis. The liquid rises at the sides. If the radius of the vessel is 0.05 m and the speed of rotation is 2 rev/s, find the difference in the heights of liquid at the centre of the vessel and at its sides.

                                                                              

Q6

The pressure difference between two points along a horizontal pipe, through which water is flowing, is 1.4 cm of mercury. If, due to non-uniform cross-section, the speed of flow of water at the point of greater cross-section is 60 cm/s, calculate the speed at the other point. Density of mercury . 

Q7

Water flows into a horizontal pipe whose one end is closed with a valve and the reading of a pressure gauge attached to the pipe is . This reading of the pressure gauge falls to  when the valve is opened. Calculate the speed of water flowing into the pipe.

Q8

Air is streaming past a horizontal aeroplane wing such that its speed is 120 ms–1 at the upper surface and 90 ms–1 at the lower surface. If the density of air is 1.3 kg/m3, find the difference in pressures between the two surfaces of the wing. If the wing is 10 m long and has an average width of 2 m, then calculate the gross lift on it.      

Q9

A horizontal tube has different cross-sectional areas at points A and B. The diameter of A is 4 cm and that of B is 2 cm. Two manometer limbs are attached at A and B. When a liquid of density 0.8 g/cm3 flows through the tube, the pressure-difference between the limbs of the manometer is 8 cm. calculate the rate of flow of the liquid in the tube. (g = 980 cm/s2  

Q10

Water tank has a hole in its wall at a distance of 10 m below the free surface of water. The diameter of the hole is 2 mm. Compute the velocity of efflux of water from the hole and the rate of flow of water. (g = 9.8 m/s2