00:01
Hi students let me explain to the question here this is the hemispical shape tank so it having the radius 10 feet and the tank it is completely fulled so we have to find the work done work done in pumping all water pumping all water out of the tank to a level of two feet above the top of the tank so through the pumping out of tank to the pumping out of tank to a level of two feet above the top of the tank so through the pumping out of tank to a level of of two feet above the, two feet above the top of the tank.
00:42
This is the question.
00:45
So coming to the explanation here, so this will be the center of mass, center of mass of solid hemisphere.
00:55
Solid hemisphere.
01:01
So here, from the top of the tank, it will be two feet, and here, r is equal to 10 feet.
01:20
So we know that 1 feet is equal to 0 .3048 meters.
01:26
So volume of the hemisphere.
01:29
So the volume of hemisphere, it is given by the formula that is 2 by 3 pi r cube.
01:38
So here let the potential energy, potential energy.
01:44
So we have to assume potential energy.
01:47
U is equal to 0 at the center of a mass of hemisphere.
01:53
At center of mass of solid hemisphere.
02:00
Solid hemisphere.
02:05
So whenever the change in the potential energy, it is nothing but work done.
02:12
Change in potential energy it is equal to work done.
02:19
Work done.
02:21
So that means m g h, it is nothing but the work done.
02:26
So coming to the m, so that is mass of water...