A) \[F(\mathbf{\hat{i}-\hat{j}})\]
B) \[-F(\mathbf{\hat{i}}+\mathbf{\hat{j}})\]
C) \[F(\mathbf{\hat{i}}+\mathbf{\hat{j}})\]
D) \[-F(\mathbf{\hat{i}}-\mathbf{\hat{j}})\]
Correct Answer: D
Solution :
\[\overset{\to }{\mathop{\tau }}\,=\overset{\to }{\mathop{\mathbf{r}}}\,\times \overset{\to }{\mathop{\mathbf{F}}}\,\] \[\overset{\to }{\mathop{\tau }}\,=(\widehat{\mathbf{i}}-\widehat{\mathbf{j}})\times (-F\widehat{\mathbf{k}})\] \[=F[(-\widehat{\mathbf{i}}\times \widehat{\mathbf{k}})+(\widehat{\mathbf{j}}\times \widehat{\mathbf{k}})]\] \[=F[\widehat{\mathbf{j}}+\widehat{\mathbf{i}}]=F[\widehat{\mathbf{i}}+\widehat{\mathbf{j}}]\]You need to login to perform this action.
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