A mass m₁ of 100kg travelling with a uniform velocity of 5 m/s along a line collides with a stationary mass m₂ of 1000kg. After the collision, both the masses travel together with the same velocity. The coefficient of restitution is

A fluid of dynamic viscosity $$2 \times {10^{ - 5}}\,\,kg/m.s$$ and density $$1kg/{m^3}$$ flows with an average velocity of $$1$$ $$m/s$$ through a long duct of rectangular $$\left( {25\,\,mm \times \,\,15\,\,mm} \right)$$ cross-section. Assuming laminar flow, the pressure drop (in $$Pa$$) in the fully developed region per meter length of the duct is __________________.

Consider the turbulent flow of a fluid through a circular pipe of diameter, $$D.$$ Identify the correct pair of statements.
$${\rm I}.$$ The fluid is well-mixed
$${\rm II}.$$ The fluid is unmixed
$${\rm III}.$$ $$R{e_D} < 2300$$
$${\rm IV}.$$ $$R{e_D} > 2300$$

A siphon is used to drain water from a large tank as shown in the figure below. Assume that the level of water is maintained constant. Ignore frictional effect due to viscosity and losses at entry and exit. At the exit of the siphon, the velocity of water is