A pressure difference of 6.00 X 104 Pa is required to maintain a volume flow rate of 0.800 m3/s for a viscous fluid flowing through a section of cylindrical pipe that has radius 0.210 m. What pressure difference is required to maintain the same volume flow rate if the radius of the pipe is decreased to 0.0700 m?

Solution 48E Step 1: dV 3 Volume flow rate dt = 0.8 m /s Pressure difference p = 6.00 x 10 Pa 1 Radius of cylindrical pipe R = 0110 m Radius of cylindrical pipe after changing radius R = 0.070 m 2 Step 2: Since the fluid is viscous the pressure changes as the radius of the tube changes. The relationship between the change in pressure and the radius of the cylindrical tube is given by p L (assume that the length of the pipe is same) R 4