Let the angle between two nonzero vectors and be 120 o and its resultant be .

Question

Philoid · Accepted Answer

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| means the numerical difference of the magnitudes of

and

. The following diagram best illustrates the problem. The magnitude of resultant of two non-zero vectors must be greater than the difference of magnitudes of the vectors.

In figure a: we have B>A and AD=OA, CD=|A-B|. In triangle OCD angle ODC=120° so angle COD<120°, hence OC>CD because in a triangle side opposite the greater angle is greater. So, > |-|

In figure b: We have A>B and AD=CA, OA=|A-B|. In triangle OCD angle ODC =120° so angle OCD<120°, hence OC>OD because in a triangle side opposite the greater angle is greater, So, >|-|.

Let the angle between two nonzero vectors and be 120o and its resultant be .

Let the angle between two nonzero vectors and be 120^o and its resultant be .