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Please forgive me if I am being too much stupid. But please can anybody tell me why I am getting two different values of the Tension for the same pendulum. Its not at equilibrium. As it oscillate due to weight's component which provides torque due to force perpendicular to the $mg\sin(a)$.
As you can see, here I am getting tension T=mg/sin(a).
But here I am getting it as tension $ T=mgsin(a)$ .
Which one is correct or I am doing something incorrect.
$\begingroup$This is a very common mistake and you even chose the angles differently from how everybody else chooses. The two scenarios that you have considered refer to completely different physics and the 2nd one is the one that is correct. The first one is just very wrong.$\endgroup$
$\begingroup$Thanks for your response. Can you please elaborate, how and why taking the component of tension and equating it with weight is wrong?$\endgroup$
$\begingroup$Have you checked any of the other people asking the same thing? If you set the vertical component of tension equal to the weight, then the pendulum bob is accelerating horizontally, rather than tangentially to a circle. That is just way too wrong.$\endgroup$
