Advanced/Notes 9.1
-
Upload
mrshowellclass -
Category
Business
-
view
371 -
download
2
description
Transcript of Advanced/Notes 9.1
![Page 1: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/1.jpg)
Chapter 9
Static Equilibrium
![Page 2: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/2.jpg)
Conditions for Equilibrium
• What are the conditions for equilibrium?
![Page 3: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/3.jpg)
What if…
• We look at a book sitting on a table
• Is it moving?
![Page 4: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/4.jpg)
Equilibrium
• The book is experiencing forces but is not moving
• It is in equilibrium
• Latin for equal forces
![Page 5: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/5.jpg)
Braces• The wire band
around the teeth has a tension TF of 2.0 N along it. What is the resultant force on the highlighted tooth?
• Draw a force diagram of the tooth.
![Page 6: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/6.jpg)
Braces• The wire band exerts
the FT in each direction along the wire.
• Since the forces are equal and in opposite directions, the FR will be along the line that bisects the angle between them.
![Page 7: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/7.jpg)
Braces
• Call the direction of FR the y axis
• What will be the sum of the forces in the x direction?
• What will be the sum of forces in the y direction (FR)?
• Result of this?
![Page 8: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/8.jpg)
Equilibrium
• Was the tooth in equilibrium?
• First condition of equilibrium:
• Must be zero along each axis (including z!)
![Page 9: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/9.jpg)
Chandelier
• Calculate the tension FA and FB in the two cords that are connected to the vertical cord supporting the 200 kg chandelier.
• Draw a free-body diagram of what?
![Page 10: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/10.jpg)
Chandelier
• Pick the point where the three cords meet
• Sum in the forces in the x and y direction
• Resolve FA into components
![Page 11: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/11.jpg)
Equilibrium
![Page 12: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/12.jpg)
Equilibrium?
![Page 13: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/13.jpg)
Equilibrium
• The forces add up to zero, but…
• The forces produce a net torque that will rotate the object
• Couple: A pair of equal forces acting in opposite directions but at different point in on object
![Page 14: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/14.jpg)
Equilibrium
• Second condition for equilibrium:
• The sum of the torques must be zero
![Page 15: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/15.jpg)
Lever
• A bar is placed over a small rock to act as a lever on the large rock
• The lever should allow a smaller FP
• What if FP is still not large enough?
![Page 16: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/16.jpg)
Mechanical Advantage
• Torque of FP must be equal or greater than mg so we can say
• mgr = FPR
• Rearrange
• Define Mechanical Advantage as r/R
![Page 17: Advanced/Notes 9.1](https://reader036.fdocuments.in/reader036/viewer/2022062312/55413255550346c46e8b4597/html5/thumbnails/17.jpg)
Homework
• Read Section 9.1