What pressure difference is required between the ends of a 2.0-m-long, 1.0-mm-diameter horizontal tube for 40 C water to flow through it at an average speed of 4.0 m/s?

Answer : The pressure difference required is,

Explanation : Given,

Length of tube = 2.0 m

Diameter of tube = 1.0 mm = 1.0 × 10⁻³

Average speed of water = 4.0 m/s

Viscosity of water at 40°C = 0.7 × 10⁻³

The expression used for pressure difference is:

where,

= pressure difference

= viscosity of water = 0.7 × 10⁻³

L = length of tube = 2.0 m

A = area of tube =

= average speed of water = 4.0 m/s

Now put all the given values in the above expression, we get:

Thus, the pressure difference required is,