Rolling Ball

• 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.