Density and Viscosity of the Fluid:
The given fluid has a density of 100 kg/m3 and a viscosity of 0.5 N-s/m2. Density is a measure of how much mass is contained in a given volume, while viscosity is a measure of a fluid's resistance to flow.

Tube Diameter:
The tube through which the fluid is flowing has a diameter of 20 cm. To calculate the maximum velocity of the fluid, we need to convert this diameter to meters.

- Diameter = 20 cm = 0.2 m

Flow Conditions:
The problem states that there is no turbulence in the flow. This means that the flow is considered to be laminar, where the fluid moves in smooth, parallel layers. In laminar flow, the velocity profile is parabolic, with the maximum velocity occurring at the center of the tube.

Calculating the Maximum Velocity:
To find the maximum velocity of the fluid, we can use the Hagen-Poiseuille equation, which relates the flow rate, pressure difference, viscosity, and dimensions of the tube.

- Flow Rate (Q) = (π * r^4 * ΔP) / (8 * η * L)

Where:
- r is the radius of the tube (equal to half of the diameter)
- ΔP is the pressure difference across the tube
- η is the viscosity of the fluid
- L is the length of the tube

In this case, we are looking for the maximum velocity, which is the maximum flow rate per unit area. Since the tube is cylindrical, the flow area is given by:

- Flow Area (A) = π * r^2

We can rearrange the Hagen-Poiseuille equation to solve for the maximum velocity (v):

- v = Q / A = (π * r^4 * ΔP) / (8 * η * L * π * r^2) = (r^2 * ΔP) / (8 * η * L)

Substituting the Given Values:
- r = 0.1 m (radius is half the diameter)
- ΔP = ? (unknown pressure difference)
- η = 0.5 N-s/m2 (fluid viscosity)
- L = ? (unknown length of the tube)

Assuming Unknown Values:
Since the length of the tube is not given, we can assume it to be 1 meter for simplicity. Similarly, we can assume a pressure difference of 1 Pascal for ease of calculation.

Calculating the Maximum Velocity:
Substituting the values into the equation, we get:

- v = (0.1^2 * 1) / (8 * 0.5 * 1) = 0.01 / 4 = 0.0025 m/s

Final Answer:
The maximum velocity of the fluid flowing through the tube is 0.0025 m/s. Rounding this value to the nearest integer, we get the answer as '0' instead of '50', as mentioned. However, it is possible that there might be a calculation error or incorrect interpretation of the problem statement. Please double-check the given information and calculations to ensure accuracy.

For no turbulency, Reynolds number must be critical.