1. Practicing Supports and 2FM’s
Lesson 20
Practicing Supports and 2FM’s

2. How Many Unknowns? ?

3. How Many Unknowns? Ax ?
Pin Ay

4. How Many Unknowns? Ax
Roller Ay By

5. How Many Unknowns? ?

6. How Many Unknowns? Ax Ay

7. How Many Unknowns? Ax MA
Fixed Ay

8. How Many Unknowns? ?

9. How Many Unknowns?
Normal! Dy

10. How Many Unknowns? ?
Normal! Dy

11. How Many Unknowns? Ax Ay
Normal! Dy

12. How Many Unknowns?
Or (if you want…)
Ay’
Ax’ Dy

13. How Many Unknowns? ?

14. How Many Unknowns?

15. How Many Unknowns?

16. How Many Unknowns?
“Smooth contact”

17. How Many Unknowns?
“Smooth contact”

18. How Many Unknowns?
“Smooth contact” = Normal !

19. How Many Unknowns?
“Smooth contact” = Normal !

20. How Many Unknowns? x y
“Smooth contact” = Normal !

21. How Many Unknowns?

22. How Many Unknowns?

23. How Many Unknowns?
Smooth collar B is fixed to the rod AB, but is allowed to slide along CD.

24. How Many Unknowns?
Smooth collar B is fixed to the rod AB, but is allowed to slide along CD.

25. How Many Unknowns?
Smooth collar B is fixed to the rod AB, but is allowed to slide along CD.

26. Find the 2-Force Member (2FM)

27. Find the 2-Force Member (2FM)
CD is 2FM

28. Find the 2-Force Member (2FM)
ABD is NOT 2FM

29. Find the 2-Force Member (2FM)
ABD is NOT 2FM

30. Important Contrast: Pin-Ended Member is not the same as Hole in a Solid Member
Solid Member with a hole in it.

31. Important Contrast: Pin-Ended Member is not the same as Hole in a Solid Member
2FM
Solid Member with a hole in it.