1. Force Vectors

2. Equilibrium of Forces

3. Moments from Forces (I)

4. Moments from Forces (II)

5. Illustrations for Forces and Moments

6. Force Couples

7. Transmissibility of Forces

8. Force/Moment Resultants

9. Equivalent Loading (I)

10. Equivalent Loading (II)

11. Practical Examples

12. Typical 2-D Supports (I)

13. Typical 2-D Supports (II)

14. Free Body Diagram (I)

15. Free Body Diagram (II)

16. Free Body Diagram (III)

17. Free Body Diagram (IV)

18. Two/Three Force Members When a member is subject to no couple moments and the applied forces can be combined to be resultants at only two points, the member is called a Two-Force Member. If a member is subject to three forces, then it is necessary for them to be either concurrent or parallel when this member is in equilibrium. Such a member is called a Three-Force Member.

19. Application of Two/Three Force Members

20. Redundant Constraints

21. Statically Indeterminate Structure A x = 0,A y + C y = 500 N --------- (2) C y * 5 m + M A = 500 N * 4 m ----------- (3) A y * 5 m - M A = 500 N * (5 - 4) m ----- (4) 5 m 4 m { (3) + (4) (2) Cannot solve for all unknowns !!!

22. Tricky Problems

23. Truss Structures

24. Truss Analysis

25. Joint Method (I)

26. Joint Method (II)

27. Zero-Force Members (a) (b) (a) (b)

28. Exercise Example

29. Internal Forces/Moments

30. Section Method (I)

31. Section Method (II)