Question
Two vectors have magnitudes 3 unit and 4 unit respectively. What should be the angle between them if the magnitude of the resultant is:
- 1 unit.
- 5 unit.
- 7 unit.
✓
Answer
$|\vec{\text{a}}|=3\text{m},|\vec{\text{b}}|=4$
$\Rightarrow\theta=180^{\circ}$
Angle between them is 0°.
- If R = 1 unit
$\Rightarrow\theta=180^{\circ}$
- $\sqrt{3^2+4^2+2.3.4\cos\theta}=5$
- $\sqrt{3^2+4^2+2.3.4\cos\theta}=7$
Angle between them is 0°.
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