Vector $\vec a$ is directed due north with $|\vec a| = 24$ and vector $\vec b$ is directed due west with $|\vec b| = 7$. The magnitude $|\vec a + \vec b|$ equals:
A17
B25
C31
D$\sqrt{527}$
Answer & Solution
Correct answer: B. 25
North and west are perpendicular, so $|\vec a + \vec b| = \sqrt{|\vec a|^2 + |\vec b|^2} = \sqrt{576 + 49} = \sqrt{625} = 25$.
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