First slide

Vectors

Question

If $\vec{A} = 3 \hat{i} + 4 \hat{j}$ and $\vec{B} = 7 \hat{i} + 24 \hat{j}$ , the vector having the same magnitude as $\vec{B}$ and parallel to $\vec{A}$ is

Moderate

A

$5 \hat{i} + 20 \hat{j}$
B

$15 \hat{i} + 10 \hat{j}$
C

$20 \hat{i} + 15 \hat{j}$
D

$15 \hat{i} + 20 \hat{j}$

Solution

$| \vec{B} |$ = $\sqrt{7^{2} + {(24)}^{2}} = \sqrt{625} = 25$
Unit vector in the direction of A will be $\hat{A} = \frac{3 \hat{i} + 4 \hat{j}}{5}$
So required vector = $25 (\frac{3 \hat{i} + 4 \hat{j}}{5}) = 15 \hat{i} + 20 \hat{j}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App