2.9-2.11

2.9 Equilibrium of a Particle
equilibrium
resultant of all forces acting on a particle is zero
Newton’s First Law
If the resultant force on a particle is zero, the particle will remain at rest or will continue at constant speed in a straight line

2.11
Free-Body Diagrams

Space Diagram

 A sketch or picture of the problem



Free Body Diagram FBD
sketch showing the forces on a selected particle

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