Units, Dimensional Analysis, and Conversion Factors: Example Problems

Try to solve these problems before watching the solutions in the screencasts.

Example Problem 1

Convert 5 N to lbm-cm/min2

Note: 1 N = 1 kg-m/s2

Example Problem 2

The following equation can be used to calculate the Reynold’s number (Re) of fluid flowing in a pipe:

\[Re\, = \, \frac{\rho\,D\,\nu}{\mu}\]

where \(D\) is the pipe diameter, \(\nu\) is the fluid velocity, \(\rho\) is the fluid density, and \(\mu\) is the fluid viscosity. Calculate the Reynold’s number for a fluid flowing through a pipe of diameter 4.3 inches having the following properties: \(\nu\) = 0.037 ft/s, \(\rho\) = 1.3 g/mL, and \(\mu\) = 0.57 centipoise (cP) (1 cP = 1.00×10-3 Pa-s).