Question

A highly rigid cubical block `A` of small mass `M` and side `L` is fixed rigidly on the other cubical block of same dimensions and of modulus of rigidity `eta` such that the lower face of `A` completely covers the upper face of `B`. The lower face of `B` is rigidly held on a horizontal surface . `A` small force `F` is applied perpendicular to one of the side faces of `A`. After the force is withdrawn , block `A` executes faces of `A`. After the force is withdrawn , block `A` exceutes small oscillations , the time period of which is given by
A. `2 pi sqrt(M eta L)`
B. `2 pi sqrt((M eta//L))`
C. `2 pi sqrt((ML// eta))`
D. `2 pi sqrt((M// eta L))`

Answer 1

Correct Answer - d
`[eta] = [ML^(-1)T^(-1)]`
hence` [sqrt((M)/(eta L))] = sqrt(([M])/([ML^(-1)T^(-1)][L])) = [T]`