UNIT 4
Conditions for Static Equilibrium
Example 1
Example 2
Example 3
Example 4
Example 5
Example 6
Mechanical Properties of Solids
Example 1
Example 2
Example 3
Example 4
Example 5
Example 6

 

 

Questions and Answers on Static Equilibrium

 
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5. An beam is holding two masses, m1 (10kg) and m2 (30 kg) in equilibrium.
(a) Calculate the force F if the pivot is at X.
(b) What would F become if the pivot is moved to Y?

Fig 5.
Answer  

(a) The system is in equilibrium so
∑Torques about any point = 0
Clockwise Torques + Anticlockwise Torques = 0.

Taking Torgues at X
τclockwise+ τanticlockwise = 0

[-(m1g X 2m)] + [-(m2g X 16m)] + (F X 14)] = 0

14 F - (100N X 2m) -(300N X 16m) = 0

14F = 4800 + 200

F = 357N

Supplementary Explanations:
Recall from Newton's First and Second Laws the conditions for static equilibrium:
— Its angular momentum (momentum_angular)about its center of mass, or about any other point, is also zero.

Taking Torgues at Y
τclockwise+ τanticlockwise = 0

[-(m2g X 6m)] + (F X 2) + (m1g X 8m) = 0

2 F + (100N X 8m) [-(300N X 6m)] = 0

2F + 800 = 1800

F = 500N

Supplementary Explanations:
Recall from Newton's First and Second Laws the conditions for static equilibrium:
— Its angular momentum (momentum_angular)about its center of mass, or about any other point, is also zero.
     
     
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Concept by Kishore Lal. Programmed by Kishore Lal... Copyright © 2015 Kishore Lal. All rights reserved.