Lift a hemispherical dome filled with water by rotating it

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SUMMARY

The discussion centers on calculating the minimum angular velocity required to lift a hemispherical dome filled with water, specifically a dome with a radius of 2 meters and a weight of 30 tons. The initial answer proposed was 2.91 rad/s, while the correct minimum angular velocity is established at 1.95 rad/s. Participants express confusion regarding the mechanics of how angular velocity influences the lifting of the dome and clarify that the water remains inside the dome during this process.

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Homework Statement


A hemispherical dome filled with water, radius 2 m and weight 30 tons, can be lifted by giving it a constant angular velocity around its vertical line of symmetry. The dome has a hole on the top. Decide the minimum angular velocity.

My answer is 2.91 rad/s .
The correct answer is 1.95 rad/s.

Homework Equations


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The Attempt at a Solution


Shown in the attached picture.
phys.png
 
Last edited:
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I don't understand this problem . Angular velocity of what ? How does whatever it is act on the hemisphere to lift it ??
 
Nidum said:
I don't understand this problem . Angular velocity of what ? How does whatever it is act on the hemisphere to lift it ??
I'm sorry, I have tried to make the problem clearer now :)
 
How does rotating something cause translation? Sounds like a breach of conservation of momentum?

Edit: So the water isn't lifted, just the hemisphere?
 

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