In a vertical smooth hollow thin tube, a block of same mass as that of tube is released as shown. When it is slightly disturbed it moves towards right. By the time the block reaches the right end of the tube, the displacement of the tube will be (where ‘R’ is the mean radius of tube, assume that the tube remains in vertical plane).

Options

A. (a)`(2R)/(pi)`
B. (b)`(4R)/(pi)`
C. (c)`R/2`
D. (d)`R`

Answer

C

Explanation

Let x: displacement of the tube towards left. `S_(cm) = (-Mx + M(R - x))/(M + M) = 0 implies x = R//2`.