\(4 i -3 j +7 k \) and  \(4 i... - Solved | MCA Prep" /> \(4 i -3 j +7 k \) and  \(4 i... - Solved | MCA Prep" /> \(4 i -3 j +7 k \) and 

Question 44

Mathematics Scalar and Vector Products Hard

Forces&nbsp;<span class="math-tex">\(4\hat{i}-3\hat{j}+7\hat{k}\)</span>&nbsp;and&nbsp;<span class="math-tex">\(-2\hat{i}+2\hat{j}-8\hat{k}\)</span>&nbsp;are acting on a particle and displaced it from the point (5, 7, 1) to (2, 5, -6), then the work done by the force is

(A) 2
(B) 9
(C) 3
(D) 1
โœ“ Correct Answer: Option C Verified Solution

๐Ÿ“˜ Step-by-Step Solution & Detailed Explanation:

Total force \(\vec{F} = (4 - 2)\hat{i} + (-3 + 2)\hat{j} + (7 - 8)\hat{k} = 2\hat{i} - \hat{j} - \hat{k}\)

Displacement \(\vec{d} = (2-5)\hat{i} + (5-7)\hat{j} + (-6-1)\hat{k} = -3\hat{i} - 2\hat{j} - 7\hat{k}\)

Work = \(\vec{F} \cdot \vec{d} = -6 + 2 + 7 = 3\)

Answer: (C) 3

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