Question

A body of mass $1kg$ is travelling with constant velocity of $3m/s$ due East. It then turns North to travel with a constant velocity of $4m/s$. Find the impulse acting on the body due to change in its direction in vector form. (Take east and north as positive x-axis and y-axis respectively)

• A. $3\hat{j}-3\hat{i}N–s$
• B. $4\hat{j}-3\hat{i}N–s$
• C. $4\hat{i}-3\hat{j}N–s$
• D. $4\hat{j}-4\hat{i}N–s$

Answer 1

The correct option is B $4\hat{j}-3\hat{i}N–s$

$\overrightarrow{p}$$=(m\times \overrightarrow{v}$)

$\overrightarrow{p_i}$$=(1\times 3)\hat{i}$

And $\overrightarrow{p_f}$$=(1\times 4)\hat{j}$

$\therefore \overrightarrow{J}=\overrightarrow{p_f}-\overrightarrow{p_i}$

$=4\hat{j}-3\hat{i}N–s$