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Relating Pendulum SHM

  1. Jun 12, 2012 #1
    I've seen in many sites that a pendulum restoring force Fnet = mg sin theta... Why did we actually get the vector direction of the weight and not the vector of the tension.. Simply, as in centrepetal force.. It would be Tsin theta would be the net restoring force??? Thanks!
  2. jcsd
  3. Jun 12, 2012 #2
    The restoring force is the net force acting on the pendulum's bob.
    If you add the tension and the weight (as vectors) and consider inextensible suspension string the resultant is tangent to the trajectory and its magnitude is mg sinθ.
  4. Jun 12, 2012 #3
    Can i have illustrations then??
  5. Jun 13, 2012 #4
    Sure you can. Draw the forces acting on the pendulum and then take the components along the tangential and radial directions.
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