ch03 - Chapter3 :Statics ChapterObjectives...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
Engineering Mechanics: Statics Chapter 3:  Equilibrium of a Particle 
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chapter Objectives To introduce the concept of the free-body  diagram for a particle. To show how to solve particle equilibrium  problems using the equations of equilibrium.
Background image of page 2
Chapter Outline Condition for the Equilibrium of a  Particle  The Free-Body Diagram Coplanar Systems Three-Dimensional Force Systems
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
3.1 Condition for the  Equilibrium of a Particle  Particle at  equilibrium  if - At rest - Moving at constant a constant velocity Newton’s first law of motion F  = 0 where ∑ F  is the vector sum of all the  forces acting on the particle 
Background image of page 4
3.1 Condition for the  Equilibrium of a Particle  Newton’s second law of motion F  = m a When the force fulfill Newton's first law  of motion,  m = 0   = 0 therefore, the particle is moving in  constant velocity or at rest
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
3.2 The Free-Body Diagram Best representation of all the unknown  forces (∑ F ) which acts on a body A sketch showing the particle “free” from  the surroundings with all the forces acting  on it Consider two common connections in this  subject –  Spring        –  Cables and Pulleys
Background image of page 6
3.2 The Free-Body Diagram Spring - Linear elastic spring: change in length is  directly proportional to the force acting on it spring constant or stiffness k defines the elasticity of  the spring - Magnitude of force when spring  is elongated or compressed F  =  k s  
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
3.2 The Free-Body Diagram Spring where s is determined from the difference in  spring’s deformed length l and its  undeformed length l o s = l - l o   - If s is positive,  F  “pull” onto the spring - If s is negative,  F  “push” onto the spring  
Background image of page 8
3.2 The Free-Body Diagram Example  Given l o  = 0.4m and  k  = 500N/m To stretch it until l = 0.6m,  A force,  F  =  k =(500N/m)(0.6m – 0.4m) = 100N is needed To compress it until l = 0.2m,   A force,  F  =  k =(500N/m)(0.2m – 0.4m) = -100N is needed
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
3.2 The Free-Body Diagram Cables and Pulley - Cables (or cords) are assumed to have  negligible weight and they cannot stretch - A cable only support tension or pulling force - Tension always acts in the  direction of the cable - Tension force in a continuous cable must have a constant  magnitude for equilibrium  
Background image of page 10
3.2 The Free-Body Diagram Cables and Pulley - For any angle  θ , the cable is  subjected to  a constant tension  T   throughout its length  
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
3.2 The Free-Body Diagram Procedure for Drawing a FBD  1.  Draw outlined shape - Isolate particle from its surroundings 2. Show all the forces - Indicate all the forces
Background image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 62

ch03 - Chapter3 :Statics ChapterObjectives...

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online