How is density of sand calculated by using water?Describe in brief.
A glass doesnot immerse in water when dipped straight downwards. Why?
What is effort arm?
plz answer it..

Density of sand calculated by using water given below.

A glass doesnot immerse in water when dipped straight downwards is explained in the following way

Explanation:

Density is the mass per unit volume. Divide the mass of the sand by the volume of the sand.Calculate the air space volume.It will be equal to the volume of the sand alone plus the volume of the water alone minus the volume of the sand/water mixture.Air pressure. The water is trying to get up into the bottle from underneath, which means that the air inside has nowhere to go. ... That's because there's more water pressure deeper down, and that pressure compresses the air more and more, making room for the water to get further and further inside.When an empty glass bottle is inverted into a vessel, containing water, the water doesn't enter the glass bottle because of the air present in bottle. The air occupies space and thus the water can only enter if the air is given a way to get out of the bottle ( this can be done by slightly tilting the bottle).