Force System Resultants

Moment of a Force Scalar Formulation :

Lecture 5

1

If the numerical result of this sum is a positive scalar , (MR)O will be a

counterclockwise moment , and if the result is negative , (MR)O will be a

clockwise moment .

Examples :

2

Solution :

Principle of Moments :

It states that the moment of a force about a point is equal to the sum of

the moments

3

4

Example :

Solution I :

Solution II :

Example :

Determine the moment of the force as shown in figure about point O .

5

Moment of a Couple :

Solution :

6

Example :

7

Solution :

Example :

8

Solution :