NEET Physics-02 Rotation, Gravitation and Properties of Matter

From center of mass to satellites in orbit: explore the physics that turns tricky formulas into clear problem-solving tools. If you’ve ever wondered why the center of mass isn’t “just the midpoint,” or why a rolling ring loses a race to a solid sphere, you’ll find the connections here. Start by learning to locate the center of mass for two particles and for rigid bodies—including classic cut-out disc problems using “negative mass”—and see why internal forces can’t shift the motion of the system’s center of mass. Then move into rotational kinematics with angular displacement, velocity, and acceleration, using the constant‑α equations (in radians) and practical reminders like not mixing rpm with rad/s. Torque, equilibrium, and moment of inertia are built step by step: moment arms, couples, the two equilibrium conditions, radius of gyration, and standard NEET-ready I values for rods, rings, discs, spheres, and shells—plus parallel and perpendicular axes theorems (and when not to use them). Rotational dynamics follows with τ = Iα, angular momentum conservation, and rolling without slipping, tying linear and rotational ideas together. You’ll also cover gravitation and satellites (g variation, Kepler’s laws, potential vs potential energy, escape and orbital speed, satellite energy) and key properties of solids and fluids—stress–strain, moduli, hydrostatics, viscosity, Bernoulli, surface tension, and core heat concepts from expansion to calorimetry and heat transfer.