Consider ..n.. number of indentical cubes each of mass ..m.. and side ..a.. lying on a level ground. Find work done in piling them one above the other.

Consider ..n.. number of indentical cubes each of mass ..m.. and side

1.	Consider ..n.. number of indentical cubes each of mass ..m.. and side ..a.. lying on a level ground. Find work done in piling them one above the other.
Answer» Solution :The initial total POTENTIAL energy of all the blocks lying on the ground is ` U_(1) = nxxmg""(a)/(2)` The potentia energy, when the blocks are piled to form a single COLUMN is `U_(2) = nmg""(na)/(2) = N ^(2) MG""(a)/(2)` `THEREFORE` Work done in arranging the blocks one above the other is `W = U_(2) - U_(1)` `W=n^(2)mg""(a)/(2)-nxxmg""(a)/(2)(n^(2)-n)` or `W = mg""(a)/(2)n (n-1)`