Force System 2D - Tewodros · PDF file•Categories depending on their arrangement in plane Coplanar collinear forces Definition Cont Coplanar parallel forces Coplanar concurrent forces

Chapter II

Force Systems 2DForce Systems 2D

Definition

• A force can be defined as the action of one body on

another that changes/tends to changes the state of

the body acted on.

• A force can be applied on a body as;

�Contact force:-Applied by direct mechanical contact of �Contact force:-Applied by direct mechanical contact of

the acting body on the acted one (Created by push and

pull).

�Remote action (Body force):-Applied by remote action as

in gravitational, electrical, Magnetic, etc forces.

AAITAAITAAITAAIT Engineering Mechanics StaticsEngineering Mechanics StaticsEngineering Mechanics StaticsEngineering Mechanics Statics Department of Department of Department of Department of Tewodros N. Civil Engineering

• Categories of force depending on their

arrangement in space.

� Coplanar Forces:- are forces which act on the

same plane.

Definition Cont…

same plane.

� Non coplanar forces:- are forces which act on

different planes » Non coplanar parallel forces

» Non-coplanar concurrent forces

» General Non coplanar force


• Categories depending on their

arrangement in plane

� Coplanar collinear forces

Definition Cont…

� Coplanar collinear forces

� Coplanar parallel forces

� Coplanar concurrent forces

� General coplanar forces


• Coplanar collinear forces:- are coplanar forces

acting on the same line-collinear.

• Coplanar parallel forces:- Are forces which are

Definition Cont…

• Coplanar parallel forces:- Are forces which are

on the same plane and parallel


• Coplanar concurrent forces:- Are forces on the

same plane whose lines of action intersect at a

point.

Definition Cont…


• General coplanar forces

Definition Cont…






Ɵ














Example 2/3

Given vector A with the following properties:

Magnitude= 150, Ɵz =450, Ɵy= 600, and it is known

that Ax is directed in the positive x direction. Express

the vector in Cartesian form.

Example 2/4

Example 2/3

Given vector A with the following properties:

Magnitude= 150, Ɵz =450, Ɵy= 600, and it is known

that Ax is directed in the positive x direction. Express

the vector in Cartesian form.

Example 2/4

Determine a unit vector normal to the plane of the


Determine a unit vector normal to the plane of the

triangle formed by three points: (0,0,2), (2,0,0), and

(0,2,0)as its vertices.

Example 2/3Example 2/

A vector F has a magnitude of 2 and is directed from

point A to point B as shown in the figure below.

Calculate the projection of this vector onto line CD

and determine also the angle between F and CD.

5




Definition

•Moment (torque )

•Tendency of a force to •Tendency of a force to

rotate a body about a

given axis.






























bbbbbbbbbbbbb


Couple

• moment produced by 2 equal and

opposite forces is known as a

couple.couple.


Couple Cont…

• Moment of couple about any point

of reference 0.


• Moment of couple about any point of

reference 0.

Couple Cont…


• Moment of couple about any point of

reference 0.

Couple Cont…


Couple Cont…


Couple Cont…

• Resolution of a force into a force and a

couple equal external effect.


Force System 2D - Tewodros · PDF file•Categories depending on their arrangement in plane Coplanar collinear forces Definition Cont Coplanar parallel forces Coplanar concurrent forces

Documents