Glycerine flows steadily through a horizontal tube of a length of 1.5 m and a radius of 1.0 cm. If the amount of glycerine collected per second at one end is 4.0 × 10^–3 kg s^–1, what is the pressure difference between the two ends of the tube?
(Density of glycerine = $1.3\times {10}^3$ kg m^–3 and viscosity of glycerine = 0.83 Pa-sec).
1. 7.9 × 10⁻² Pa
2. 8.9 × 10⁻³ Pa
3. 9.8 × 10⁻² Pa
4. 6.7 × 10⁻³ Pa

What is the largest average velocity of blood flowing in an artery of radius \(2\times 10^{-3}\) m if the flow must remain laminar?
(Take the viscosity of blood to be \(2.084\times 10^{-3}\) Pa-s and density of blood to be \(1.06\times 10^3\) kg/m³).
1. \(0.459\) m/s
2. \(0.0987\) m/s
3. \(0.983\) m/s
4. \(0.0897\) m/s