the negative sign of the moment with respect to the pivot indicates that the moment tends to decrease the angle thata

Thanks for an interesting and clear presentation

I just love your lecture can i have some discussion over the topic that how can i improve my basics of physics??

Hi you might be able to help me. With the physical pendulum I understand that an equation relating torque to angular acceleration times the moment of inertia around the pivot (I_a), is the way to solve it: mlgphi+(I_a)phi double dot (where we use the usual small angle approximation sin(phi) as phi). But could you tell me why a simple equation using Newton's second law on the centre of mass along the phi hat direction of the circular arc through the centre of mass doesn't work. In other words: mgphi+mphi double dot=0. The reason I ask is translational motion for an extended body can be described using Newton's second law as long as we use the mass m and the centre of mass. Then shouldn't the net force applied at every instant through the centre of mass act in the phi hat direction and be equal to the mass times the acceleration in the phi hat direction. I'm obviously overlooking something as the physical pendulum isn't reducible to the simple pendulum. Can you shed light on this. I would appreciate any help. Thanks.

wait... isn't the general solution to y'' + y = 0 -> acos(x) + bsin(x)

good explanation thank you

This was good!

Excellent

sir, Is there any difference between moment of inertia and rotational inertia?

you are awasome man

what if pivot was in middle of pendulum?

what's k?