So, just to clarify:
In order to determine the instantaneous angular acceleration of a half-filled bottle of water tipping over - i.e. rotating about the point where it touches the table - I use the moment of inertia for a rigid body with the same instantaneous shape as the water (which will...
But in this case the water would have to accelerate. Wouldn't it?
Does that mean the moment of inertia for the water should be ignored when the bottle is falling over?
Consider a partially filled bottle of water. When it's tipped over and rotating about its pivot point where its edge touches the ground, it has an angular acceleration. Assuming the liquid is not viscous at all, so flows perfectly, at a given instant can it be considered to have a moment of...