Question

11) A body has its centre of mass at the origin. The x-coordinates of the particles

(A) may be all positive
(B) may be all negative
(C) may be all non-negative
(D) may be positive for some cases and negative in other cases

Answer 1

(c) may be all non-negative
(d) may be positive for some cases and negative for other cases

According to the question, the centre of mass is at origin.

∴ X = m1x1 + m2x2 + m3x3 +...m1 + m2 + m3 +....... = 0
⇒m1x1 + m2x2 + m3x3 +... = 0

From the above equation, it can be concluded that all the x-coordinates may be non-negative.

In other words, they may be positive for some cases and negative for others.

Answer 2

Answer:

A,D

Explanation:

All co-ordinates positive will make the co-ordinate of com positive.

All co-ordinates negative will make the co-ordinates of com negative.

If all the co-ordinates are zero(0), co-ordinate of com is zero(0).

If  co-ordinate of com can be zero,  co-ordinates of some are positive and co-ordinates of some are negative.