Is there a buoyant force at the bottom of the ocean?

Answer 1

I suspect you mean the gravitational acceleration constant which is about 9.81 m/s^2. This value is actually only valid at Earth's surface (and it also varies from place to place). So in general the answer to your question is no. It might, but it won't be in general.

The value is calculated by using Newton's Law of gravitation: F = G m1*m2 / r^2. Where F is the gravitational force, m1 is the mass of the Earth and m2 is the mass of an object. r is the distance from the object to the center of the Earth. Because r does not differ much, G is just a constant (called Newton's Gravitational Constant), and m1 also does not change much, we usually do the following:

If we are interested in the acceleration an object experiences due to gravity we can use Newton's Second Law: F = m * a.

If we take m as the mass of our object, and a its acceleration due to the gravitational force we must have:

G m1 * m / r^2 = m * a

If we cross out the m (or m2) on both sides we end up with:

a = G m1 / r^2

This a is usually called g. It does not vary much in everyday life, but it does ultimately, so g varies with height.

Answer 2

Yes there is.

But the amount of upward buoyant force from the water cannot overcome the density of the object (which is obviously more dense than water, or the object wouldn't be at the bottom of the ocean.)

Answer 3

Yes, you only float because of the buoyancy force, which counteracts gravity . Gravity is a result of the mass of an object.