Kinematics Question 258
If $ \overset{\to }{\mathop{A}}\times \overset{\to }{\mathop{B}}=-\overset{\to }{\mathop{B}}\times \overset{\to }{\mathop{A}} $ then the angle between A and B is [AIEEE 2004]
Options:
A) $\pi / 2 $
B) $\pi / 3 $
C) $\pi $
D) $\pi / 4$
Show Answer
Answer:
Correct Answer: C
Solution:
We know that $ \overrightarrow{A}\times \overrightarrow{B}=-(\overrightarrow{B}\times \overrightarrow{A}) $
because the angle between these two is always 90°.
But if the angle between $ \overrightarrow{A} $ and $ \overrightarrow{B} $
and $ \overrightarrow{B} $ is 0 or $\overrightarrow{p}$.
Then $ \overrightarrow{A}\times \overrightarrow{B}=-\overrightarrow{B}\times \overrightarrow{A} \neq 0 $ .
BETA
