Kinematics Question 447
Question: Find a vector of magnitude 5 along BA where coordinates of points A and B are (0, 1, 3) and (1, 4, 6) respectively
Options:
A) $ ( \frac{5}{\sqrt{19}} )[\hat{i}+3\hat{j}+3\hat{k}] $
B) $ -( \frac{5}{\sqrt{19}} )[\hat{i}+3\hat{j}+3\hat{k}] $
C) $ 5[\hat{i}+3\hat{j}+3\hat{k}] $
D) $ -5[\hat{i}+3\hat{j}+3\hat{k}] $
Show Answer
Answer:
Correct Answer: B
Solution:
[b] $ \overset{\to }{\mathop{BA}}=\overset{\to }{\mathop{OA}}-\overset{\to }{\mathop{OB}}=(\hat{j}+3\hat{k})-(\hat{i}+4\hat{j}+6\hat{k}) $
$ =-\hat{i}-3\hat{j}-3\hat{k} $
Unit vector along $ \overset{\to }{\mathop{BA}}=-\hat{i}-3\hat{j}-3\hat{k}/\sqrt{19} $
BETA
