CBSE-XI-Physics
09: Centre of Mass, Linear Momentum, Collision
- #2If all the particles of a system lie in X-Y plane, is it necessary that the centre of mass be in X-Y plane?Ans : Yes, if all the particles of a system lie in the X-Y plane, then it's necessary that its centre of mass lies in the X-Y plane.
`` {z}_{\mathit{cm}}=\frac{{m}_{1}{z}_{1}+{m}_{2}{z}_{2}+...{m}_{n}{z}_{n}}{{\displaystyle \underset{}{\sum }}m}``
As all the particles lie in the X-Y plane, their z-coordinates are zero.
Therefore, for the whole system, zcm = 0; i.e., its centre of mass lies in the X-Y plane.
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