A balloon filled with air is weighted so that it barely floats in water
Answers
Answer:
Assuming that "barely able to float" means that it still IS able to float, then it's density is still less than water's and it will return to the surface after being pushed below the surface.
However, if by "barely able to float" the questions means that the weighted balloon's density is the same as water's, then it will not return to the surface of the water; it will just continue to float at the depth that it was pushed to.
Here is the solution to the above question:
Boyle'slaw states that for a fixed amount of gas in a closed system at constant temperature, the product of the pressure and the volume is equal to a constant. If the pressure goes up, the volume goes down. If the weighted balloon is pushed down under the surface of the water, the water pressure on the outside of the balloon increases. This will cause the balloon to shrink .
The shrunken balloon displaces less water than it did before. This means that it experiences a reduced buoyant force. The balloon's weight, however, has not changed. Now that the force of gravity on the balloon exceeds the buoyant force, the balloon will sink.