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Allushta [10]
2 years ago
9

Find the magnitude of the sum of two vectors; A is 5 km , and B is 7 , when the angle btween them is 120

Physics
1 answer:
Dimas [21]2 years ago
4 0

Answer: 6.24 km

Explanation:

Given

The magnitude of the first vector(say) \left |  a\right |=5\ km

the magnitude of the second vector(say) \left |  b\right |=7\ km

the angle between them is 120^{\circ}

The resultant vector magnitude is given by

\left |  \vec{R}\right |=\sqrt{a^2+b^2+2ab\cos \theta}

\left |  \vec{R}\right |=\sqrt{5^2+7^2+2\times 5\times 7\cdot \cos 120^{\circ}}\\\left |  \vec{R}\right |=\sqrt{74-35}=\sqrt{39}\\\left |  \vec{R}\right |=6.24\ km

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