Question

The velocity of a projectile at the initial point $\text{A}$ is $(2\hat{i}+3\hat{j}){\text{ms}}^{-1}.$ It's velocity (in ${\text{ms}}^{-1}$) at point $\text{B}$ is -

• A. $2\hat{i}+3\hat{j}$
• B. $-2\hat{i}-3\hat{j}$
• C. $-2\hat{i}+3\hat{j}$
• D. $2\hat{i}-3\hat{j}$

Answer 1

The correct option is D $2\hat{i}-3\hat{j}$

As the projectile travels from point $A$ to $B$, the $x-$component of velocity will remain, in magnitude and direction. The $y-$component changes in both magnitude and direction.
The magnitude of $y-$component of velocity, at points $A$ and $B$ is the same, but the directions are opposite.

$\therefore V_B=2\hat{i}-3\hat{j}$

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, $\left(D\right)$ is the correct answer.