Physics 9702 · AS & A Level · SI units

SI units — practice question

The Reynolds number $R$ is a constant employed in the analysis of liquids moving through pipes. $R$ is a dimensionless quantity, so it has no unit. $R = \frac{\rho v D}{\mu}$ where $\rho$ represents the density of the liquid, $v$ is the liquid's speed and $D$ is the diameter of the pipe in which the liquid flows. What are the SI base units of $\mu$?

  • A$\text{kg m s}$
  • B$\text{kg m}^{-1}\text{s}$
  • C$\text{kg m s}^{-1}$
  • D$\text{kg m}^{-1}\text{s}^{-1}$

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