Read the two statements and choose the correct option. I. If a · b = 0 and neither vector is 0, the vectors are perpendicular. II. a · b = b · a, and likewise a × b = b × a.

Question 62

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Read the two statements and choose the correct option.
I. If $\vec{a} \cdot \vec{b} = 0$ and neither vector is $\vec{0}$ , the vectors are perpendicular.
II. $\vec{a} \cdot \vec{b} = \vec{b} \cdot \vec{a}$ , and likewise $\vec{a} \times \vec{b} = \vec{b} \times \vec{a}$ .

Only ICorrect answerYour answerOnly IICorrect answerYour answerBoth I and IICorrect answerYour answerNeither I nor IICorrect answerYour answer

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CorrectNot quiteAnswer A

Correct answer: A

I: $\lvert \vec{a} \rvert \lvert \vec{b} \rvert \cos \theta = 0$ with both magnitudes non-zero forces $\cos \theta = 0$ . True.
II: the scalar product commutes, but $\vec{b} \times \vec{a} = -\vec{a} \times \vec{b}$ . False.

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