The vector sum of a system of non-collinear forces acting on a rigid body is given to be non-zero. If the vector sum of all the torques due to the system of forces about a certain point is found to be zero, does this mean that it is necessarily zero about any arbitrary point?

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Payal Gupta | Contributor-Level 10

9 months ago

This is a short answer type question as classified in NCERT Exemplar

no $\sum_{i} F_{i} \neq 0$

The sum of torques about a certain point O $\sum_{i} r_{i} * F_{i} = 0$

The sum of torques about any other O $\sum_{i} r_{i} F_{i} = 0$

The sum of torques about any other point O'

$\sum_{i} (r_{i} - a) * F_{i} = \sum_{i} r_{i} * F_{i} - a * \sum_{i} F_{i}$

Here the second term need not vanish.

Sum of all torques about any point is zero.

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