Rotational Motion | Lec: 07 | Rotation About Fixed Axis Part-2 | JEE NEET Physics By DS Sir Kota

Deepen your understanding of Rotational Mechanics with DS Sir (Kota) in this second part of "Rotation About Fixed Axis." This lecture moves beyond ideal pulleys to explore systems where pulleys have mass and moment of inertia. Learn how to solve complex multi-body problems involving translational and rotational motion, including double-pulley systems, inclined planes with rotating discs, and hinged rod systems. DS Sir provides Kota-level techniques for establishing constraint relations between linear acceleration ($a$) and angular acceleration ($\alpha$) and setting up torque equations. Essential for JEE Mains, JEE Advanced, and NEET students. Video Timestamps: [00:00] - introduction [00:10] - Recap: Ideal vs. Non-Ideal Pulleys in Newton's Laws [02:55] - Why Tensions ($T_1, T_2$) differ in a rotating pulley system [04:10] - Setting up Equations for Translation and Rotation (Net Torque = $I\alpha$) [09:00] - Deriving Acceleration ($a$) for a mass-pulley system [09:42] - Illustration 1: Block and Pulley with Moment of Inertia [14:57] - Illustration 2: Pulley over Pulley (Double Pulley) System [18:06] - Constraint Relations for different radii in Double Pulleys [25:30] - Illustration 3: Block on an Inclined Plane connected to a Disc [30:16] - Solving for $a, \alpha,$ and Tension in the Inclined Plane system [31:06] - Finding Distance and Velocity after time '$t$' using Equations of Motion [33:20] - Illustration 4: Hinged Rod connected to a falling mass [35:15] - Writing Torque equations for a rotating rod about a hinge [37:31] - Establishing $a = L\alpha$ constraint for the Rod-Block system [39:03] - Final Calculation of Acceleration and Tension for the Rod system