Question

Center of mass of three particles $10kg,20kg,30kg$ is at $(0,0,0)$. Where should a particle of mass $40kg$ be placed so that the combined center of mass will be at $(3,3,3)$?

• A. $(0,0,0)$
• B. $(7.5,7.5,7.5)$
• C. $(1,2,3)$
• D. $(4,4,4)$

Answer 1

The correct option is B $(7.5,7.5,7.5)$

$3=\frac{(60\times 0)+(40\times x)}{60+40}$

$\therefore x=7.5$

Similarly $y=7.5$

$z=7.5$

Hence coordinate =$(7.5,7.5,7.5)$