The function $$f\left( z \right) = {{{z^2} + 1} \over {{z^2} + 4}}$$ is singular at

In abrasive water jet machining, the velocity of water at the exit of the orifice, before mixing with abrasives, is 800 m/s. The mass flow rate of water is 3.4 kg/min. The abrasives are added to the water jet at a rate of 0.6 kg/min with negligible velocity. Assume that at the end of the focusing tube, abrasive particles and water come out with equal velocity. Consider that there is no air in the abrasive water jet. Assuming conservation of momentum, the velocity (in m/s) of the abrasive water jet at the end of the focusing tube is _________.

A vertical cylindrical tank of $$1$$ $$m$$ diameter is filled with water up to a height of $$5$$ $$m$$ from its bottom. Top surface of water is exposed to atmosphere. A hole of $$5$$ $$m{m^2}$$ area forms at the bottom of the tank. Considering the coefficient of discharge of the hole to be unity and the acceleration due to gravity to be $$10\,\,m/{s^2}$$, the rate of leakage of water (in litre/min) through the hole from the tank to the atmosphere, under the given conditions, is ______________

In a fully developed turbulent flow through a circular pipe, a head loss of ݄$${{h_1}}$$ is observed. The diameter of the pipe is increased by $$10\% $$ for the same flow rate and a head loss of ݄$${{h_2}}$$ is noted. Assume friction factor for both the cases of pipe flow is the same. The ratio of $${{{h_2}} \over {{h_1}}}$$is closest to