A Newtonian liquid at 20°C (p = 900 kg/m³ = 800 cP) flows through a straight pipe having a diameter of 4 cm and length of 20 m (laminar flow). Pressures at the inlet and outlet of the pipe are measured to be 750 and 100 kPa, respectively. If the pipe is inclined 20° to the horizontal plane and the flow is downward, calculate the volumetric flow rate.