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  • SUBJECT:-ENGINEERING MECHANICS
  • SEMESTER:- 2nd semester

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  • CHAPTER : 2
  • TOPIC : EQUILIBRIUM
  • PREPARED BY :-ER.B.C.PANDEY
  • (Asst.HOD Mechanical Engineering Dept.)

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Equilibrium

if the resultant of a number of forces, acting on a particle is zero, the particle will be in equilibrium. Such a set of forces, whose resultant is zero, are called equilibrium forces. The force, which brings the set of forces in equilibrium is called an equilibrant.

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PRINCIPLES OF EQUILIBRIUM

  • 1.Two force principle.

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  • As per this principle, if a body in equilibrium is acted upon by two forces, then they must be equal, opposite and collinear.

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2. Three force principle.

As per this principle, if a body in equilibrium is acted upon by three forces, then the resultant of any two forces must be equal, opposite and collinear with the third force.

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3. Four force principle.

As per this principle, if a body in equilibrium is acted upon by four forces, then the resultant of any two forces must be equal, opposite and collinear with the resultant of the other two forces.

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LAMI’S THEOREM

  • It states, “If three coplanar forces acting at a point be in equilibrium, then each force is proportional to the sine of the angle between the other two.”

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THANK YOU