There is a fluid flowing in a pipeline. A situation arrives where we are required to reduce the pressure in the pipe to prevent it from bursting. Which among the following is the best solution?

Q. Consider steady flow of water in a situation where two pipe lines (pipe 1 and pipe 2) combine into a single pipe line(pipe 3) as shown in figure. The cross-sectional area of all three pipelines are constant. The following data is given

Pipe number	Area$\left(m^2\right)$	Velocity (m/s)
1	1	1
2	2	2
3	2.5	?

Assuming the water properties and the velocities to be uniform across the cross-section of the inlets and the outlet, the exit velocity (in m/s) in pipe 3 is

Q. It is given that rate of heat transfer in convection is directly proportional to area of plate across which fluid flows$A$,density of fluid ($\rho$), velocity of flow ($V$),temperature difference ($t$) with proportionality constant of 2 units.Also fluid is flowing across edge to edge on a square plate of side length of 0.1 unit with density of fluid is 10 units and velocity of 2 units. Then what will be the rate of heat conducted through the plate if temperature difference between plate and fluid is unity?(assume that all $units$ are in international standards)

Q. Two pipes of diameters $d_1$ and $d_2$ converge to form a pipe of diameter d. If the fluid flows with a velocity of $v_1$ and $v_2$ in the two pipes, what will be the flow velocity in the third pipe ?

Q. A horizontal pipe of non uniform cross section has water flow through it such that the velocity is $2m{s}^{-1}$ at a point where the pressure is $40kPa$. The pressure at a point where the velocity of water flow is $3m{s}^{-1}$ is : ( in $kPa$)