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Physics · PYQ NEET UG 2016(2)
हिन्दीA particle moves from a point \( (-2\hat{i} + 5\hat{j}) \) to \( (4\hat{j} + 3\hat{k}) \) when a force of \( (4\hat{i} + 3\hat{j}) \text{ N} \) is applied. How much work has been done by the force?
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Correct answer · Option D
\( 5 \text{ J} \)
Explanation
Displacement \( \vec{r} = (0 - (-2))\hat{i} + (4 - 5)\hat{j} + (3 - 0)\hat{k} = 2\hat{i} - \hat{j} + 3\hat{k} \). Work \( W = \vec{F} \cdot \vec{r} = (4)(2) + (3)(-1) + (0)(3) = 8 - 3 = 5 \text{ J} \).
