THE SIMPLE PENDULUM

The Simple Pendulum consist of a small metal weight or bob suspended from a rigid support with a thread . when this bob is tilted , it performs a simple harmonic motion . the air resistance gradually reduces this motion until the bob stop to oscillate .

EXPRESSION FOR PERIOD  T

From the figure above,

                                  At equilibrium (vertical position)

F=weight of the bob =mg

When the bob is displaced through an angle Ï´

Restoring force F = -mgsin Ï´

For small Ï´,      sin Ï´≈ Ï´  

Therefore F=-mg Ï´

But        (note that length of arc = ) in radian 

Therefore     

F=ma   therefore  a =    

For a simple harmonic motion ,  

The Period T is

In a simple harmonic Motion,     

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