Irodov 1.267 Explained Beautifully by Tyagi Sir 🔥 | Rotation Problem

Added: 2026-05-21

[00:00:00]Come on kids, let me ask you a question from Aerodoff today.

[00:00:02]Which is based on rotation and if you do not know the solution of this question then you will have to attend my lecture on angular momentum. First let me solve this question for you that there is a sphere which is doing pure rolling.

[00:00:18]Omega1 and Omega angular velocities are given.

[00:00:20]Let the radius of the sphere be r. And this distance from the axis to the center, we take that distance l not. So here we take this distance l n o center to axis, this distance l n o and we have taken the radius of the sphere brother r now see the total kinetic energy this will be the total kinetic energy this is a question of Irodof and I will write it in two ways, one is 1/2 i 2 / 5mr² * omega1² this rotation rotational kinetic energy plus translational kinetic energy v will be equal to l n o * omeg2 so let us write that one also 1/2m v² okay plus this third rotation omega2 should be understood by every good child, for this this rigidly about this axis this angular velocity will be same omeg2 2K this is very less clear to the children. I'll still write that term down as well, so this is going to be 1/2 i 2 / 5 mr² * omeg2². This is one way to write the total kinetic energy of this sphere. The second way is that you write this term as it is this term. And by combining these two terms you can say that it is doing pure rotation about this axis.

[00:01:54]This sphere is rigidly connected. And take out i about this axis. Plus i about this axis 1/2 i omeg2² and both of these terms, this term and this term, will be the same. This term which comes will be equal to this. Now, you just have to make this one correction in this. Put this value here and you will get the same term.

[00:02:21]So this is the solution for total kinetic energy. But if any child has not understood this then please attend my lecture on angular momentum and rotational motion.

[00:02:30]I will explain all these things in clarity. All the best.