Five uniform circular plates, each of diameter `b` and mass `m` are laid out in a pattern shown. Using the origin shown, find the `y` co-ordinate of the centre of mass of the five-plate system.
.

Options

A. `b//5`
B. `b//3`
C. `4b//5`
D. `2b//5`

Answer

C

Explanation

( c) `y_(cm) = (m. 0 + m.0 + m.b + mb +m^2 b)/(5 m) = (4b)/(5)`.