A cylinder has a radius 20 cm. To what height should it be filled with water so that thrust in its walls is equal to that on its bottom? Find the mass of water filled in cylinder.

Explanation

Let h is the height of water in cylinder, r is radius of cylinder and p =density of water
T=Thrust on the walls `=((pgh)/(2)) xx (2pirh)`
T.=Thrust at the bottom =`(pgh) xx pir^(2)`
As T=T, `therefore ((pgh)/(2)) xx 2pirh=pgh xx pir^(2)`
h=20cm