1. Statics (ENGR 2214) Prof. S. Nasseri Units of Measurement ENGR 2214 Dr Simin Nasseri MET Department, SPSU

2. Statics (ENGR 2214) Prof. S. Nasseri Definitions Basic Quantities are: Length (Meter, Foot) Time (Second) Mass (Kilogram, Slug) Force (Newton, Pound force) Units: Basic quantities (force, mass, length, time) are related by Newton’s second law. Units used to measure quantities are not all independent. Three of four units (mass, length, time), called base units, are arbitrarily defined and the fourth (force) is derived.

3. Statics (ENGR 2214) Prof. S. Nasseri Units SI unitsU.S. customary units (fps) Modern version of metric system, Base units are Meter or m for length, Second or s for time and Kilogram or kg for mass, Acceleration of gravity: g = 9.8 m/ s 2 Force is derived quantity measured in unit called Newton: 1 N = 1 kg. m / s 2 Base units are: Feet (ft) for length, Second (s) for time, and Pound (lb) for force, Acceleration of gravity: g = 32.2 ft / s 2 Mass is derived quantity measured in a unit called a slug: 1 slug = 1 lb. s 2 / ft

4. Statics (ENGR 2214) Prof. S. Nasseri Units NameLengthTimeMassForce SIMeter (m)Second (s)Kilogram (Kg)Newton (N) US customaryFoot (ft)Second (s)slug (lb.s 2 /ft)Pound (lb) Unit conversions: Force: 1 lb = 4.4482 N Mass: 1 slug = 14.5938 kg length: 1 ft = 0.3048 m

5. Statics (ENGR 2214) Prof. S. Nasseri Conversion factors