Question 1.7: The pascal (Pa) is actually a very small unit of pressure. T...
The pascal (Pa) is actually a very small unit of pressure. To show this, convert 1~{\mathrm{Pa}}=1~{\mathrm{N}}/{\mathrm{m}}^{2}~\mathrm{to}~\mathrm{lb}/\mathrm{ft}^{2}. Atmospheric pressure at sea level is 14.7 lb/in² . How many pascals is this?
Using Table 1–2, we have
1\;\mathrm{Pa}={\frac{1\;\mathrm{N}}{\bf m^{2}}}\bigg({\frac{1\;\mathrm{lb}}{4.4482\;\mathrm{N}}}\bigg)\bigg({\frac{0.3048^{2}\,\mathrm{m}^{2}}{1\;\mathrm{ft}^{2}}}\bigg)=20.9\bigg(10^{-3}\bigg)\;\mathrm{lb/ft}^{2}
1~{\mathrm{ATM}}={\frac{14.7~\mathrm{lb}}{\mathrm{in}^{2}}}\left({\frac{4.448~\mathrm{N}}{1~\mathrm{lb}}}\right)\left({\frac{144~\mathrm{in}^{2}}{1~\mathrm{ft}^{2}}}\right)\left({\frac{1\;\mathrm{ft}^{2}}{0.3048^{2}\,\mathrm{m}^{2}}}\right)
=\;101.3\Big(10^{3}\Big)\;\mathrm{N/m^{2}}
=\;101\;{\mathrm{kPa}}