Hi UTAlumnus

Pressure or stress is normally measured in Pascals. 1 Pascal can be expressed as 1 Newton per metre squared. 1 Newton = 1 kilogram metre per second squared.
Therefore 1 Pascal = 1 kilogram per metre second squared.

All the SI dervived units such as resistance (ohms), magnetic flux (webers) etc can be reduced down to expressions of the SI base units of measurement.

length meter = m
mass kilogram = kg
time second = s
electric current ampere = A
thermodynamic temperature = Kelvin K
amount of substance mole = mol
luminous intensity candela = cd

Each SI base unit is a fundemental reference value and is extremely accurate and precise.

This is what makes the SI system so universal in regards to scientific measurements as all calculations are base 10 not base 12, 9, 16, 8 etc or combintations of each as in the imperial system of measurement. 10 squared = 100 and 10 cubed = 1000.

The ratio between psi and psf is 144 (12 times 12 i.e 12 squared) whereas the ratio between Pa and kPa is 1000 (the k indicates 1000 and M would indicates 1 million i.e MPa = 1 Million Pa)