Question

A particle follows uniform motion along line from P $(2,4,6)$ to Q$(4,8,2)$ with a speed of $12$ m/s. Find velocity vector of the particle.

• A. $2\hat{i}+4\hat{j}-4\hat{k}$
• B. $4\hat{i}+8\hat{j}-8\hat{k}$
• C. $12(2\hat{i}+4\hat{j}-4\hat{k})$
• D. none

Answer 1

The correct option is B $4\hat{i}+8\hat{j}-8\hat{k}$

$\overrightarrow{v}=\left(12m/s\right)\text{unit vetcor}$
$=12\frac{2\hat{i}+4\hat{j}+4\hat{k}}{\sqrt{2^2+4^2+4^2}}$
$=12\frac{\{2\hat{i}+4\hat{j}-4\hat{k}\}}{6}$
$\overrightarrow{v}=4\hat{i}+8\hat{j}-8\hat{k}$