A) 10 unit
B) \[-10\]unit
C) 9 unit
D) \[-9\]unit
E) None of the above
Correct Answer: E
Solution :
Resultant force is \[\overrightarrow{F}=(2\hat{i}-5\hat{j}+6\hat{k})+(-\hat{i}+2\hat{j}-\hat{k})\] \[=\hat{i}-3\hat{j}+5\hat{k}\] and displacement, \[\overrightarrow{d}=\overrightarrow{AB}\] \[=(6\hat{i}+\hat{j}-3\hat{k})-(4\hat{i}-3\hat{j}-2\hat{k})\] \[=2\hat{i}+4\hat{j}-\hat{k}\] \[\therefore \] Work done\[=W=\overrightarrow{F}.\overrightarrow{d}\] \[=(\hat{i}-3\hat{j}+5\hat{k}).(2\hat{i}+4\hat{j}-\hat{k})\] \[=2-12-5=-15\] \[=15\text{ }unit.\] \[(neglecting\text{ }-\text{ }ve\text{ }sign)\]
You need to login to perform this action.
You will be redirected in
3 sec
