A) \[25\]
B) \[13\]
C) \[26\]
D) \[28\]
Correct Answer: B
Solution :
Given that, \[{{\vec{F}}_{1}}=3\hat{i}-2\hat{j}+\hat{k}\]and \[{{\vec{F}}_{2}}=\hat{i}-3\hat{j}+5\hat{k}\]and \[\overrightarrow{OA}=-2\hat{i}+5\hat{k}\] and \[\overrightarrow{OB}=-3\hat{i}-7\hat{j}+2\hat{k}\] Total force \[\vec{F}={{\vec{F}}_{1}}+{{\vec{F}}_{2}}=4\hat{i}-5\hat{j}+6\hat{k}\] and displacement \[\vec{d}=\overrightarrow{OB}-\overrightarrow{OA}\] \[=-\hat{i}-7\hat{j}-3\hat{k}\] \[\therefore \] Work done \[=\vec{d}.\vec{F}\] \[=(-\hat{i}-7\hat{j}-3\hat{k}).(4\hat{i}-5\hat{j}+6\hat{k})\] \[=-4+35-18\] \[=13\]
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