Chapter 9: Rotational Dynamics

Pure translational motion

All points on an object move in parallel paths.

Torque

A turning force causing angular acceleration, calculated as the magnitude of force multiplied by the lever arm.

Lever arm

The distance from the axis of rotation to the line of action of the force.

Rigid body equilibrium

When an object has zero translational and angular acceleration.

Center of gravity

The point where an object's weight effectively acts when calculating torque.

Moment of Inertia

The resistance of an object to changes in its motion, calculated as mass times the square of the distance to the axis of rotation.

Rotational work

Energy transformation due to torque over a distance, leading to a change in rotational kinetic energy.

Rotational kinetic energy

Energy of a rotating object due to its rotation, calculated as half the moment of inertia times the square of the angular velocity.

Angular momentum

The product of an object's moment of inertia and its angular velocity around the same axis.

Principle of Conservation of Angular Momentum

Angular momentum remains constant if the net external torque acting on the system is zero.