What is meant by "SI units," "newtons" and "pascals"?

The correct designation of the current international metric system is the "International System of Units." which is abbreviated "SI." The "newton" is a unit of force. In the SI system the kilogram is restricted to measurements of mass, not force. For this reason in strength tests the newton (N) is the unit to be used. (Most countries and much of the literature still employ improper terminology when referring to concrete strengths, designating strength in terms of kilograms force per square centimeter kgf/cm2) When pressure or stress is to be designated the unit to use is the " pascal" (Pa). The pascal is the pressure or stress in terms of newtons per square meter (Pa = N / m2) . Following are some convenient values for making conversions :

### Force

Customary U.S. Units / Original Metric Units / SI Units

1.000 pound | 0.4536 kilogram | 4.448 newtons

2.2048 pounds | 1.000 kilogram | 9.80665 newtons

0.2248 pound | 0.102 kilogram | 1.00 newton

### Pressure of Stress

Customary U.S. Units / Original Metric Units / SI Units

100.0 psi | 7.03 kgf/cmc 2 | 689.4757 kPa (kN/m2)

1422.0 psi | 100.00 kgf/cm | 9806.65 kPa (kN/m2)

14.62 psi | 1.028 kgf/cm | 100.0 kPa (kN/m2)

The term "kPa" is one thousand pascals and "kN" is one thousand newtons.Further information may be found in ASTM E 380-72 in Part 30 of the 1972 Annual Book of ASTM Standards.