A4 - Rigid body Mechanics

Newton’s first law for rotational motion

An object moves at a constant angular velocity unless an external torque acts on it

Newton’s third law for rotational motion

When object A applies a torque to object B, then object B with apply an equal and opposite torque to object A

Conservation of angular momentum

The total angular momentum of a system remains constant providing no external torque acts on the system

Rolling

the object is rotating across a surface about an axis of rotation

Sliding

the object is moving smoothly along a surface. When an object is on a perfectly frictionless surface, it can’t roll, only slide.