Normally you can assume that the density of the liquid won't change much; nor the density of the sinking object. Therefore, the buyant force won't change significantly.
the gravitational force will decrease
Density
no
Two things reduce the force of gravity between two objects: an increase in the distance between the two objects or decrease in mass of the two objects
The buoyant force will be greater on the object in the denser fluid.
the gravitational force will decrease
You sink.
Decrease the distance between them.
Yes it does.
At a greater distance, the gravitational force becomes less.
Density
Buoyant force is based upon the mass of the water displaced. Therefore, two objects will have the same buoyant force if they have the some volumes.
The buoyant force is 135N
No, it actually might decrease due to balloon being compressed by pressure. Floating objects are governed by Archimedes Principle which states that the weight of a floating object is equal to the water it displaces. A corollary of Archimedes Principle is that the buoyant force acting on an object is equal to the volume of water displaced. Therefore, when a balloon is compressed as it submerges it displaces less water and the buoyant force decreases proportionately.
no
Two things reduce the force of gravity between two objects: an increase in the distance between the two objects or decrease in mass of the two objects
If the weight of an object is greater than its buoyant force, then it will not float - it will sink.