Common JEE Traps in Rotation

Applying perpendicular axis theorem to 3D bodies — it only works for planar (2D) bodies
Forgetting parallel axis theorem when the axis is not through the CM — I is always minimum about the CM axis
Assuming tensions are equal across a massive pulley — they are not; the difference drives the pulley's rotation
Confusing angular velocity and angular frequency — both use omega, but the context differs (rotation vs oscillation)
Using kinetic friction for rolling without slipping — the friction is static, not kinetic, in pure rolling
Ignoring the rolling constraint — if the problem says "rolls without slipping," you MUST use v = R*omega
Thinking heavier objects roll slower — mass cancels out in rolling acceleration; only the shape ( $k^2$ / $R^2$ ) matters