Question 14
A uniform rod 1 m long is suspended at its exact centre and balanced. A weight of 4 N is now hung at one end. What moment does it produce?
The right answer is the one marked above.
2 N m. The rod hangs from its exact centre, so the distance from the centre to the end is 0.5 m. moment = 4 N × 0.5 m = 2 N m.
Using the full 1 m length of the rod gives 4 N m, and that is the trap. Distance is measured from the point of suspension, not from the far end.