Physics - Newtonian Mechanics

bonkysleuth SG

Why is a glass that is filled with liquid less stable than an empty glass?

I think this can be explained by the "lesser base area" theory. Can anyone help me elaborate or correct me if I'm wrong? Or do I explain in terms of te centre of gravity theory??

FirePig SG

centre of gravity is higher on a glass filled with water. When the wind blows, the glass only needs to tilt a little and the whole structure will fall. Think of it like stacking uno stacko.

4794 SG

i though is the glass filled with liquid more stable? sincer it is heavier,the cg will be lower?

FirePig SG

i though is the glass filled with liquid more stable? sincer it is heavier,the cg will be lower?

oh ya. Depends on what the glass is made of on the base and the sides.

eagle SG

TS, where did you see this question?

Darkness_hacker99 SG

i though is the glass filled with liquid more stable? sincer it is heavier,the cg will be lower?

I'm thinking about this too

bonkysleuth SG

TS, where did you see this question?

O, that's extracted from my workbook. Eh, I find this question a little strange too. But I suppose it's got to do with the CG being a little higher. Yea, that's what i think.

eagle SG

does it have a drawing of the glass? Slanted or straight sides?

Darkness_hacker99 SG

It also depend on what external factor that cause the glass container to be unstable.

Example: Using a detonator charge in an empty glass container.

Of course the forces will be dissipate and there won't be a significant shocked wave produce.

HOWEVER if the glass container is filled with water, things will be different.

Quote: Wiki
Initial damage to a target will be caused by the first shockwave; this damage will be amplified by the subsequent physical movement of water and by the repeated secondary shockwaves or bubble pulse.

weewee SG

assuming glass is symmetrical, cg will be at the base of glass when empty. when water is added, cg will rise in height, making it easier to topple.

however, when water is added, the weight is increased and more force will be needed to topple the glass.

eagle SG

assuming glass is symmetrical, cg will be at the base of glass when empty. when water is added, cg will rise in height, making it easier to topple.

however, when water is added, the weight is increased and more force will be needed to topple the glass.

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the sentences in blue contradict each other.

weewee SG

sentence in red is not true.

the sentences in blue contradict each other.

oh ya you are right.

CG can be at a point which is not touching the glass....\*/

When a bit of water is actually added, the CG will be lowered and thus stabilised the glass.

When a lot of water is added in (water level mark way above original CG), the CG will be heightened and destabilised the glass.