Question

A fisherman and his young niece are in a boat on a small pond. Both are wearing life jackets. The niece is holding a large hellium balloon by a string. Consider each action below independently and indicate wether the level of water in the pond, Rises, Falls or is Unchanged

1.The fisherman knocks the tackle box overboard and it sinks to the bottom.

2.The niece gets in the water and pops the hellium ballon

3.The fisherman fills a glass with water from the pond and drinks it.

4.The fisherman lowers the anchor and it hangs one foot above the bottom of the pond.

5. The fisherman lowers himself in the water and floats in his back.

6. The niece pops the hellium balloon.

Explain plz!

Answer 1

Concept is, if floating mass remains same (without popping of balloon), buoyant force remains same and level remains unchanged and if part of mass sinks, buoyant force decrease and and level falls. Hence

If all objects in the boat, keep floating, remaining in contact with boat or not, water level remains unchanged.

If an object in boat sinks to bottom, water level falls.

If balloon is poped from the boat or by a floating person, it decreases buoyant force of water and water level falls.

Hence

In cases 1, 2 and 6 level falls and

In cases 3, 4 and 5 level remains unchanged.