- #1

Hak

- 709

- 56

Example 1:

Consider a system consisting of two material points. Suppose that the two forces acting on the two constitute a pair of forces of nonzero arm. The resultant of the forces acting on the system is zero. The resultant moment is not! Why is it that to calculate the resultant moment we add up the moments of the two forces calculated separately, thus obtaining a different result than if we calculated the moment of the resultant of the forces (which would result in a null moment)?

Example 2:

Same system, but this time the pair of forces has zero arm. Assuming that due to the effect of the two (constant) forces, the two points move by a stretch ##s##, why is the total work of the two forces derived by summing the work of the individual forces, resulting in ##2Fs##, instead of calculating the work of the resultant of the forces (which would give work equal to ##0##)?