Engineering Statics

1. Engineering Statics
MT 273
Lecture 3

2. Scalars and Vectors
• Scalar: any positive or negative physical quantity that can be
completely specified by its magnitude i.e length, mass, and time.
• Vector: any physical quantity that requires both a magnitude and a
direction for its complete description i.e force, position, and moment.

3. Vector Operations
• Multiplication and Division of a Vector by a Scalar
• Vector Addition (Parallelogram law of addition)

4. Vector Operations
• Vector Addition (Triangle Rule)
• Vector Addition (Collinear Vectors)

5. Vector Operations
• Vector Subtraction:

6. Vector Addition of Forces
• Finding Resultant Force:
• Geometrical Solution:

7. Free-body Diagram (FBD)
• To analyze forces acting on a body, it is essential that we isolate
the body in question from all other bodies so that a complete and
accurate account of all forces acting on this body can be taken.
• The diagram of such an isolated body with the representation of
all external forces acting on it is called a free-body diagram.