The Rotational Motion Series
Eight exam-ready cards covering the complete chapter for JEE Main, JEE Advanced and NEET — where Gravitation’s angular momentum grows into the most powerful toolkit in mechanics.
Centre of Mass: The Point That Behaves Like a Particle
The explosion proof, boat-and-man problems, the negative-mass trick for cut-out shapes — plus the Fosbury flop and car-rollover engineering.
Torque: Why Doorknobs Live Far From Hinges
Both faces of rF·sinθ, the zero-torque gold, and the strategic-pivot method that solves hinged-rod problems in three lines.
Moment of Inertia: Rotational Mass, Distribution Beats Size
The r² law, the standard-results table, both axis theorems chained — flywheels, cricket bats, I-beams and satellite despin.
Torque Equals I-Alpha: Newton’s Second Law, Spun
The full linear↔rotational dictionary; massive-pulley problems solved by the two-equations-one-bridge pattern.
Angular Momentum in Rotation: Conservation Unleashed
The skater’s arithmetic, merry-go-round catches, bullet-strikes-door — and why L survives collisions that destroy KE.
Rolling Motion: Translation and Rotation in One Body
The great incline race derived (sphere beats disc beats ring), the 5/7 number, and why ABS brakes exist.
Rotational Energy and Flywheels: Spin as a Battery
W = τθ and P = τω — engine ratings decoded; the yo-yo as a rolling problem; grid flywheels and F1 KERS.
Equilibrium and Toppling: Why Cranes Don’t Fall Over
The tipping line, slide-vs-topple criterion tanθ = b/h, the ladder classic — plus the complete chapter formula card.