Kinematics Question 296
Question: The value of $ (\overrightarrow{A}+\overrightarrow{B})\times (\overrightarrow{A}-\overrightarrow{B}) $ it’s [RPET 1991, 2002; BHU 2002]
Options:
A) $ 14\hat{i}-38\hat{j}+16\hat{k} $
B) $ 4\hat{i}+4\hat{j}+6\hat{k} $
C) $ 21\hat{i}+4\hat{j}+4\hat{k} $
D) $ -14\hat{i}+34\hat{j}-16\hat{k} $
Correct Answer: A $ \vec{\tau }=\vec{r}\times \vec{F}=(7\hat{i}+3\hat{j}+\hat{k})(-3\hat{i}+\hat{j}+5\hat{k}) $ $ \vec{\tau }= \begin{vmatrix} {\hat{i}} & {\hat{j}} & {\hat{k}} \\ 7 & 3 & 1 \\ -3 & 1 & 5 \\ \end{vmatrix} $ $ =14\hat{i}-38\hat{j}+16\hat{k} $
Show Answer
Answer:
Solution:
