Question:
What is Archimedes' Principle of buoyancy? How can this be
applied to building a boat?

Replies:
His principle is that something which floats must be "displacing"
an equal volume of water, and therefore will experience a force equal to the
weight of that water. So the body floats at a level equal to the quantity of
water that weighs the same amount as it does. So, when designing a boat, the
first thing you need to make sure is that the volume of the boat below the
deck (or whatever level you want to float it at) must displace a quantity of
water that weighs more than the maximum you want to carry in your boat (plus
the weight of the boat itself). You can then adjust it to float at the right
level by putting extra weights in the boat. A submarine goes up or down by
adjusting the amount of ballast it holds (by ejecting or taking on water) so
it can float anywhere, or even on the top of the sea by getting rid of all its
ballast.

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