Q.
Three rods of the same mass are placed as shown in figure. What will be the coordinates of centre of mass of the system?
A) $\left\lbrack \frac{a}{2},\frac{a}{2} \right\rbrack$
B) $\left\lbrack \frac{a}{\sqrt{2}},\frac{a}{\sqrt{2}} \right\rbrack$
C) [$\sqrt{2}a,\sqrt{2}a$]
D) $\left\lbrack \frac{a}{3},\frac{a}{3} \right\rbrack$
Explanation
(d) As shown in figure, centre of mass of respective rods are at their respective mid points. Hence centre of mass of the system has coordinates ($X_{CM}$,$\ Y_{CM}$). then
[image:7_image158.emf]
$X_{CM} = \frac{m \times \frac{a}{2} + m \times \frac{a}{2} + m \times 0}{3m} = \frac{a}{3}$
$Y_{CM} = \frac{m \times 0 + m \times \frac{a}{2} + m \times 0}{3m} = \frac{a}{3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.