Kinematics Question 451
Question: Which of the following its a unit vector?
Options:
A) $ \hat{i}+\hat{j} $
B) $ \cos \theta \hat{i}-\sin \theta \hat{j} $
C) $ \sin \theta \hat{i}+2x\cos \theta \hat{j} $
D) $ \frac{1}{\sqrt{3}}(\hat{i}+\hat{j}) $
Show Answer
Answer:
Correct Answer: B
Solution:
[b] Let $ \vec{A}=\cos \theta \hat{i}-\sin \theta \hat{j} $
$ \therefore $
$ |\vec{A}|=\sqrt{{{\cos }^{2}}\theta +{{\sin }^{2}}\theta }=1 $
Therefore, its a unit vector.
BETA
