Question

I had asked a question.why when solid body with greater density than water is when dropped from floating boat water level rises? the answer has been given that as the solid body is more dense than water displaces less fluid as compared to when it was a part of floating boat.i understood all these but this explains HOW THE AMOUNT OF DISPLACED WATER DROPS OR DECREASES BUT I AM ASKING WHY LEVEL OF WATER FALL WHEN THIS SOLID BALL WAS DROPPED FROM BOAT?I MEAN ARE BOTH SAME THING. LEVEL OF WATER WILL FALL IF AMOUNT OF DISPLACED WATER DECREASES?I REALLY DON'T UNDERSTAND WHAT WE GENERALLY MEAN WHEN SAY THAT WATER IS DISPLACED. I MEAN I KNOW OBJECT DROPPED IN WATER TAKES SOME PLACE WHERE WATER WOULD HAVE BEEN PRESENT OTHERWISE THATS WHAT WE CALL DISPLACES WATER BUT WHERE THAT DISPLACED WATER GO?WHEN BOAT IS FLOATING IT DISPLACES WEIGHT OF FLUID EQUAL TO ITS OWN WEIGHT WHERE THAT DISPLACED WATER GO?I THINK THAT DISPLACED WATER RAISE THE LEVEL OF WATER RIGHT?

Answer 1

Ok, the total water displaced is equal to the weight of the boat and the object when it is in the boat.
When the object is thrown over, it displaces water equal to its VOLUME, not weight, and it sinks. The boat now displaces its weight.
So total water displaced is LESS when the object is thrown over and it sinks. The extra force holding up the boat and weight is now provided by the ground at the bottom pushing on the weight upwards.

Before: After
weightboat+weigh are supported by the sea bouyancy
After: the weight of the boat and weight is now supported by seabouyancy PLUS the sea bottom.
So, less water is displaced after the boat sinks.