Lecture 14 - Statics

# Lecture 14 - Statics - – The sum of all the forces in z =...

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3/1/2010 1 TODAY’S TOPICS : Statics Engr 160 Statics How will learning this help me? You will learn how to ensure that structures remain safe. You will learn how to work with physical phenomena that have both magnitude and direction Free Associations with this Topic Engr 160

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3/1/2010 2 What is Force? Engr 160 The action of one body acting on another. These examples show “Free Body Diagrams” The thing that is supporting the body is replaced with equivalent forces 1. The inclined plane is replaced with a normal force 2. The support structure is replaced with a tensile force 3. The roller is replaced with a normal force 4. The hinge is replaced with a horizontal and vertical force Forces Engr 160 Forces are vectors They have magnitude They have direction θ , direction of force F y = F*sin( θ ) F x = F*cos( θ ) These pictures are equivalent
3/1/2010 3 Forces Engr Engr Engr 160 160 160 Equilibrium The sum of all the forces in y will = 0 They sum of all the forces in x will = 0

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Unformatted text preview: – The sum of all the forces in z = 0 Equilibrium FBD F T W=mg F N 45 o 60 o F T W=mg F N 45 o 60 o F Nx F Ny ( ) ( ) ( ) ( ) cos 45 cos 60 sin 45 sin 60 x Nx Tx N T y Ny Ty N T F F F F F F F F mg F F mg = = -+ = -+ = = +-= +-∑ ∑ F Ty F Tx 3/1/2010 4 Moments Hinge: Is the moment axis (the door turns around this axis) Hand Force: The force required to push the door Engr Engr Engr 160 160 160 R has to turn CCW to line up with F This is the direction of the moment Top View of Door radius Force Moments They have magnitude Moment = r x F They have direction (CW or CCW) Right Hand rule: From the moment axis draw the length of the lever arm to the force Turn the lever arm into the force This is the direction of the moment Engr 160 CCW 3/1/2010 5 Sample Problem Engr 160 pin weight Sample Problem Engr 160 pin weight 3/1/2010 6 Sample Problem Engr 160...
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## This note was uploaded on 02/09/2012 for the course ENGR 160 taught by Professor Sengupta during the Spring '07 term at Iowa State.

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Lecture 14 - Statics - – The sum of all the forces in z =...

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