Three identical smooth balls are placed between two vertical walls as shown in fig. Mass of each ball is m and radius is ` r = (5R)/(9)` where 2R is separation between the walls .
(a) Force between which two contact surface is maximum? Find its value.
(b) Force between which two contact surface is minimum and what is its value?

Answer

(a) Force between the wall and the middle ball is maximum . It is 4 mg
(b) Force between upper ball and wall is least . It is `(4)/(3)` mg.