Question

Water is flowing through a tube of radius r with a speed v. If this tube is joined to another tube of radius r/2, what is the speed of water in the second tube?

Solution

Correct option is

4v

 

From the equation of continuity of flow, we have  

            

  

              

.

SIMILAR QUESTIONS

Q1

The time period of a simple pendulum is T. The pendulum is oscillated with its bob immersed in a liquid of density . If the density of the bob is  and viscous effect is neglected, the time period of the pendulum will be

Q2

A wooden block of mass m and density  is tied to a string; the other end of the string is fixed to the bottom of a tank. The tank is filled with a liquid of density . What is the tension in the string. 

Q3

A wooden ball of density  is released from the bottom of a tank which is filled with a liquid of density  up to a height h1. The ball rises in the liquid, emerges from its surface and attains a height h2 in air. If viscous effects are neglected, the ratio h2/h1 is   

Q4

A glass plate (of negligible mass and thickness) is held against the end of a tube and pushed 10 cm under the surface of water. When released, the plate does not fall off. What depth of kerosene (relative density 0.8) must be poured into tube so that the plate just falls off?  

Q5

Water rises to a height of 13.6 cm in a capillary tube dipped in water. When the same tube is dipped in mercury, it is depressed by  cm. The angle of contact for water is zero and that for mercury 135o. The relative density of mercury is 13.6. The ratio of the surface tensions of mercury and water is   

Q6

Two blocks A and B are made of different kinds of wood. Block A floats in water with  of its above the surface water. Block B floats in water with  of its volume below the surface of water. The ratio of the densities of A and B is     

Q7

The pressures inside two soap bubbles are 1.002 and 1.004 atmospheres. Their respective volumes are in the ratio of

Q8

If W is the amount of work done in blowing a bubble of volume, V, what will be the amount of work done to blow a bubble of volume 8 V 

Q9

Equal masses of two substances of densities  are mixed together. The density of the mixture would be

Q10

Equal volumes of two substances of densities  are mixed together. The density of the mixture would be