When a solid is dropped from the boat (floating in water)into the water ,then the level of water will fall if density of that solid body is greater than density of water i.e when that solid body sinks.WHY?I tried hard ,but i am unable to figured it out according to my calculation if solid object sinks it should displace less water so water level should not rise.another question is the water level will remain unchanged if density of that solid is less than density of water i.e when that solid body floats.WHY?PLEASE HELP .
When a solid is dropped into water, the change in water level depends on the density of the solid compared to the density of water.
1. When the density of the solid is greater than the density of water:
- The solid sinks because it is denser than the water.
- When the solid sinks, it displaces an amount of water equal to its own volume.
- However, since the solid is denser than water, its volume is smaller, and thus it displaces less water compared to its own mass.
- As a result, the water level decreases slightly.
2. When the density of the solid is less than the density of water:
- The solid floats because it is less dense than the water.
- When the solid floats, it displaces an amount of water equal to its own weight.
- Since the solid is less dense, its weight is smaller compared to its volume.
- As a result, the water level remains unchanged because the weight of the water displaced by the floating solid is equal to the weight of the solid itself.
In summary, when a solid is dropped into water, the change in water level is determined by the balance between the weight or mass of the solid and the amount of water it displaces. If the solid is denser than water, it sinks and displaces less water, causing the water level to fall. If the solid is less dense than water, it floats and displaces an amount of water equal to its weight, resulting in no change in the water level.
To understand why the water level rises when a solid sinks and remains unchanged when a solid floats, we need to consider the concept of buoyancy, which is the upward force exerted by a fluid on an object immersed in it.
When a solid is floating, it displaces its own weight in water (Archimedes' principle). The weight of the water displaced is equal to the weight of the solid. Therefore, the volume of water displaced by the solid affects the water level. Since the solid is floating, its weight is balanced by the buoyant force, so the water level does not rise or fall.
On the other hand, when a solid sinks, it displaces a volume of water equal to its own volume. However, the weight of the solid is greater than the weight of the displaced water. As a result, the solid exerts a downward force on the water, causing the water level to rise. This is because the solid is not balanced by the buoyant force, and the extra weight of the solid causes an increase in the water level.
In summary, if a solid sinks, the water level rises because the weight of the solid is greater than the weight of the water it displaces. Conversely, if a solid floats, the water level remains unchanged because the weight of the solid is balanced by the buoyant force exerted by the water.
The boat and its contents are floating, so its general density is less than that of water. So, the boat displaces a volume of water which has the same mass as the boat.
But a rock is denser, so it displaces less water.
SO, the amount of water displaced drops when the rock enters the water, because it displaces less water that its share of the weight did when it was in the boat.