# Homework Help: Centre of gravity, centre of buoyancy (image)

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1. Mar 7, 2017

### Poetria

1. The problem statement, all variables and given/known data
The first image:

Without information on the interior construction of the boat or the mass distribution of the exterior shell of the boat, which of the following points can be the boat's center of gravity?

The second image:
Our boat from the previous question is now submerged in water as depicted in the figure above. Which of the following points can be the boat's center of buoyancy?

3. The attempt at a solution

I am not sure how to approach this problem.
I think for the first (centre of gravity): all points except for G would do
For the second: B, C, D, E. (the density of water is uniform)

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Last edited by a moderator: Mar 7, 2017
2. Mar 7, 2017

### Orodruin

Staff Emeritus
Why? What is the property of all the other points that G does not share?

Yes, the water is uniform. What does this tell you about the center of buoyancy? Note that the hull has a symmetric shape.

3. Mar 7, 2017

### Poetria

The force of buoyancy acts through the centroid of displaced water if the density of water is uniform. So I am wrong and only point E should be considered (as it lies exactly in the middle)?