CMGT 322 LECTURE 2

FORCES  DEFINE FORCE  DEFINE UNITS FOR FORCES  THREE IMPORTANT FACOR ABOUT FORCES: MAGNITUDE, DIRECTION, SENSE  STRESS= FORCE/AREA  UNITS FOR STRESS

LECTURE TWO  TYPES OF STRESS  COMPRESSIVE  TENSILE  SHEAR STREE  STRESS IS RELATED TO FORCE DIVIDED BY THE AREA

LECTURE TWO  COMPRESSIVE STRESS ISSUES  TENSILE STRESS ISSUES  SHEAR STRESS ISSUES  STRAIN=e/L  STRESS IS DIRECTLY PROPORSIONAL TO STRAIN

LECTURE TWO  MODULUS OF ELASTICITY=STRESS/STRAIN  Es= 30,000,000 psi  Ew= million psi  Ec= 2-5 million psi  It is important to know how stiff the material is, modulus of elasiticity

Lecture two  Five variables we need to deal with when it comes to stress strain and modulus of elasticity: –LENGTH –FORCE/LOAD –AREA –ELONGATION –MODULUS OF ELASTICITY

LECTURE TWO  CROSS SECTION ARE IS VEY IMPORTANT, WE NEED TO KNOW HOW TO CALCULATE IT  WATCH UNITS  SEE EXAMPLES