Find the distance between centre of gravity and centre of mass of a two particle system attached to the ends of a light rod. Each particle has same mass. Length of the rod is R, where R is the radius of earth.

Options

A. R
B. `R//2`
C. zero
D. `R//4`

Answer

B

Explanation

`x_(cm) = (m xx 0 + m xx R)/(m + m) = (R )/(2)`
`x_(CG) = (W_(1)(0) + W_(2)(R ))/(W_(1) + W_(2)) = (mgR)/(mg) = R`
`:. X_(CG) - x_(cm) = R - (R )/(2) = (R )/(2)`