3.17-3.21

 
 
``````````````````````````````````````````````````````````````````````````````````````````````````










3.12-3.16

 

Notes from Book:
 









3.9-3.11

 

Notes from Book
 




~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



3.1-3.8


Chapter 3 youtubes:

Statics Lecture 10: What is moment of a force?  
https://www.youtube.com/watch?v=pSK1h1Aylsk

Statics Lecture 11: Moment calculation scalar formulation
https://www.youtube.com/watch?v=_xBHygW70tE

Statics Lecture 12: Moment calculation vector formulation
https://www.youtube.com/watch?v=Lg3P4uIlgeU

Statics Lecture 13: Moment about a specified axis
https://www.youtube.com/watch?v=wfhYXm0l6BY

Statics Lecture 14: Principle of moments
https://www.youtube.com/watch?v=i7g2x8dn87Q
 
 
 
Rigid Bodies vs. Particle


Particle Problems:  Forces act through a point



Rigid Body Problems: Have to worry about moments


3 Different types of moments:


•moment of a force about a point
•moment of a force about an axis
•moment due to a couple

Any system of forces acting on a rigid body can be replaced by an equivalent system consisting of one force acting at a given point and one couple.
 




What is a "moment of a force"?*************
Any force that is applied to a rigid body causes the body to translate or rotate or both.

• The tendency to ROTATE is caused by MOMENTS generated by the force.











.







In general, a force F generates a moment about any point O which is offset by some distance from the line of action of F.

 


Review Cross products:
http://en.wikipedia.org/wiki/Cross_product
 
Notes from book:
 

 










~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~








~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~