Question

Motor oil, with a viscosity of 0.25 N ∙ s/m2, is flowing through a tube that has a radius of 3.0 mm and is 1.0 m long. The drop in pressure over the length of the tube is 200 kPa. What is the average speed of the oil

Answer 1

Answer:

The average speed of the oil is 1 m/s.

Explanation:

Given that,

Viscosity $\eta= 0.25 N-s/m^2$

Radius r = 3.0 mm

Length = 1.0 m

Pressure = 200 kPa

We need to calculate the average speed of the oil

Using formula of pressure

$\Delta P=\dfrac{8\pi\eta\rho v}{A}$

$v=\dfrac{A\times\Delta P}{8\pi\eta\rho}$

Where, A = area

$\rho$ = density of oil

$\eta$ = viscosity

Put the value into the formula

$v=\dfrac{\pi\times(3.0\times10^{-3})^2\times200\times10^{3}}{8\pi\times0.25\times0.9}$

$v=1\ m/s$

Hence, The average speed of the oil is 1 m/s.