There is a cylindrical vessel whose height and radius is known. It is filled initially with water whose level is also known. A thirsty crow with hope of quenching his thirst approaches the cylindrical vessel. He throws small pebbles, which can be approximated as small spheres, into the water. However he observes that no matter how many pebbles are thrown the water level never reaches till the mouth of the vessel. Assume that there is no leakage anywhere. The radius of the pebbles is also known(i.e can be included in the calculations) Find the condition for this to happen?
This was all that was given.
Its really a good problem. Please state if you are making any assumptions in your solution.