What is the value of Reynolds number for unsteady flow?

In deriving Bernoulli's equation,we equated the work done on the fluid in the tube to its change in the potential and kinetic energy.
$(a)$ What is the largest average velocity of blood flow in an artery of diameter $2 \times 10^{-3} \;m$ if the flow must remain laminar?
$(b)$ Do the dissipative forces become more important as the fluid velocity increases? Discuss qualitatively.

Water is conveyed through a uniform tube of $8 \text{ cm}$ in diameter and $3140 \text{ m}$ in length at the rate of $2 \times 10^{-3} \text{ m}^3/\text{s}$. The pressure required to maintain the flow is (Viscosity of water $= 10^{-3} \text{ SI units}$):

Water flows from a tap of diameter $1.5 \ cm$ with a flow rate of $7.5 \times 10^{-5} \ m^3 \ s^{-1}$. The coefficient of viscosity of water is $10^{-3} \ Pa \cdot s$. The flow is:

$A$ liquid flows through a pipe with a pressure difference of $P$. What should be the pressure difference required to maintain the same flow rate if the radius is doubled and the length is doubled?

If $R_e > 1000$,then which type of flow exists? Explain.