I'm having two independent problems while creating a table.
First, how can I center a column's top row (column's name) but keep the text of the following rows left justified?
My second problem is when I'm trying to fill one cell with the next term:
$\sqrt{\frac{\rho C_{p}r_{h}^{2}/K}{1/\omega}}$
I want the numerator and denominator to have more vertical space for better visualization.
Additionally, if there is a nicer way to represents the fractions in the numerator and denominator, that would also be helpful. I am copying all the math codes from LyX, which gave me the function \nicefrac{}{}, but apparently it's not included in my packages.

