Question

A body of mass 5 kg is moving with velocity of $\overrightarrow{v}=(2\hat{i}+6\hat{j})m/s$ at $t=2s,$ final velocity of body $(10\hat{i}+6\hat{j})$, then change in momentum of body is

• A. $40\hat{i}kgm/s$
• B. $20\hat{i}kgm/s$
• C. $30\hat{i}kgm/s$
• D. $(50i+30\hat{j})kgm/s$

Answer 1

The correct option is A $40\hat{i}kgm/s$

Given,

Initial velocity ${\overrightarrow{V}}_{initial}=(2\hat{i}+6\hat{j})m/s$

Final velocity ${\overrightarrow{V}}_{final}=(10\hat{i}+6\hat{j})$ m/s

Change in momentum $\Delta P$

$\Delta P=Mass\times ({\overrightarrow{V}}_{final}-{\overrightarrow{V}}_{initial})$

$\Delta P=5\times [(10\hat{i}+6\hat{j})-(2\hat{i}+6\hat{j}\left)\right]$

$\Delta P=40\hat{i}kgm{s}^{-1}$

Change in momentum $40\hat{i}kgm/s$