- Imagine an oil drum rolling down a hill.
- The centre of mass is the centre of the drum.
- As the drum moves down the hill, its centre of mass goes in a line (parallel with the hill).
- Velocity = 2PIrO where r is the radius of the drum and O is the angular velocity.
- Acceleration = rL where L is the angular acceleration.
- Calculate the force acting on the drum (ignore friction).
- That gives you acceleration (and velocity).
- These translate directly into their rotational equivalents.