Yiheng's youtube lectures#10-#16:
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
Statics Lecture 15: Moment of a couple
https://www.youtube.com/watch?v=mNBQKPnri3E
Statics Lecture 16: Simplification of a force and moment system
https://www.youtube.com/watch?v=FDCNEp3TQHg
Rigid Bodies vs. Particle
Treatment of a body as a single
particle is not always possible. In
general, the size of the body and the specific points of application of the
forces must be considered.
Particle Problems: Forces act through a point
Rigid Body Problems: Have to worry about moments
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.
Different Types of Forces:
External force - gravity
Internal force:
Tension or compression inside a beam
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.
Moments are Vectors
Review Cross products:
http://en.wikipedia.org/wiki/Cross_product
3.4 Vector Cross Product
3.5
3.6
3.7
3.8
Chap 3.1-3.8
See example problems 3.1, 3.2, 3.3, and 3.4 in your book
pg 87-89
Class practice problems:
3.4, 3.24
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HW3a: 2.104, 2.107, 3.9, 3.29
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3.9
3.10
3.11
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See example problems 3.5 in text pg 102.
Class examples: 3.37, 3.53
HW 3b: 3.41, 3.47, 3.74, 3.82
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