From the given diagram, what is the velocity \(v_3?\)
               
1. \(4~\text{m/s}\)
2. \(3~\text{m/s}\)
3. \(1~\text{m/s}\)
4. \(2~\text{m/s}\) 

In a horizontal pipe of a non-uniform cross-section, water flows with a velocity of \(1~\text{ms}^{-1}\)${\mathrm{}}^{}$ at a point where the diameter of the pipe is \(20 ~\text{cm}.\) The velocity of water \((\text{ms}^{-1})\) at a point where the diameter of the pipe is \(5~\text{cm}\) is:
1. \(8\)
2. \(16\)
3. \(24\)
4. \(32\)

An incompressible fluid flows steadily through a cylindrical pipe which has a radius \(2r\) at the point \(A\) and a radius \(r\) at the point \(B\) further along the flow direction. If the velocity at the point \(A\) is \(v,\) its velocity at the point \(B\) is:
1. \(2v\)                               
2. \(v\)
3. \(v/2\)                            
4. \(4v\)

The cylindrical tube of a spray pump has radius \(R,\) one end of which has \(n\) fine holes, each of radius \(r.\) If the speed of the liquid in the tube is \(v,\) then the speed of ejection of the liquid through the holes will be: