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Vectors · Question 30 of 125

Question 30

EasyOriginal question

If a⃗=i^+2j^−k^\vec{a} = \hat{i} + 2\hat{j} - \hat{k} and b⃗=3i^−j^+2k^\vec{b} = 3\hat{i} - \hat{j} + 2\hat{k}, what is 2a⃗−b⃗2\vec{a} - \vec{b}?

Options for question 30

Show the answer and explanation
CorrectNot quiteAnswer D

Correct answer: D

Explanation

  1. 2a⃗=2i^+4j^−2k^2\vec{a} = 2\hat{i} + 4\hat{j} - 2\hat{k}.

  2. Subtract component by component: −i^+5j^−4k^-\hat{i} + 5\hat{j} - 4\hat{k}.

Worth noting

−i^+5j^-\hat{i} + 5\hat{j} doubles the k^\hat{k} part of a⃗\vec{a} wrongly, −2−2-2 - 2 taken as 0.

Concept
Combining vectors
Typical time
60 s
Your time
—
The rule this testsAddition, components and the section formula
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Ten questions from Vectors, at your own pace.

Practise this chapter →

Ten questions from Vectors, at your own pace.