When a body does not merely translate but rotates, a new quantity comes into play: the moment of inertia. Rotational dynamics is the exact analogue of translational dynamics, with the moment of a force (torque) replacing force and moment of inertia replacing mass. This chapter builds the analogy step by step — angular acceleration, moment of inertia, Newton’s second law for rotation — then tackles massive pulleys, rolling bodies, conservation of angular momentum and the famous problems of the projectile against a rod and the billiard ball. The next chapter turns to universal gravitation.
Sections
- Angular acceleration
- Moment of inertia
- Newton’s second law for rotation
- Pulleys with mass
- Double-radius pulley
- Rolling bodies and rotational kinetic energy
- The complete translation–rotation analogy
- Conservation of angular momentum
- Projectile against a rod: three cases compared
- Collisions in two dimensions
- The billiard ball: where to strike?