If are three mutually perpendicular unit vectors, what is the value of ?
Answer and explanation
Correct answer: B. 7
- Step 1: Because are mutually perpendicular unit vectors, they form an orthonormal set: and .
- Step 2: Compute the squared magnitude by expanding the dot product: .
- Step 3: Take the square root to determine the magnitude: .
Answer
7.
Why not the others: The other values (11, 49, 5) arise from summing vector components linearly without squaring, or forgetting to take the square root of the sum.
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