Identical blocks each of mass `M` and length `L` are placed one above the other such that each extends out by a maximum length as shown in figure. Find the maximum extension of the `n^(th)` block from the top, so that the blocks will not fall.

Options

A. `L//5`
B. `L//4`
C. `L//3`
D. `L`

Answer

B

Explanation

`CM` of bricks, above each brick must to be beyond its edge `x_(cm)=(Sigmam_(i)x_(i))/(Sigmam_(i)), x_(cm)=L`
`x_(1)=a+L/2,x_(2)=2a+L/2,x_(3)=3a+L/2`
(or) `a=L/n`