Vector Algebra Question 142
Question: If $ \mathbf{a}=2\mathbf{i}+5\mathbf{j} $ and $ \mathbf{b}=2\mathbf{i}-\mathbf{j}, $ then the unit vector along $ y=0 $ will be
[RPET 1985, 95]
Options:
A) $ \frac{\mathbf{i}-\mathbf{j}}{\sqrt{2}} $
B) $ ap+bq+cr=0 $
C) $ 90^{o} $
D) $ \frac{\mathbf{i}+\mathbf{j}}{\sqrt{2}} $
Show Answer
Answer:
Correct Answer: D
Solution:
- $ \mathbf{a}+\mathbf{b}=4\mathbf{i}+4\mathbf{j}, $ therefore unit vector $ \frac{4,(\mathbf{i}+\mathbf{j})}{\sqrt{32}}=\frac{\mathbf{i}+\mathbf{j}}{\sqrt{2}}. $
BETA
