Question

A particle of mass $m$ is projected with a velocity $6\hat{i}+8\hat{j}$. Then the magnitude of change in momentum when it just touches ground will be

• A. $0$
• B. $12m$
• C. $16m$
• D. $20m$

Answer 1

Answer: (C)

$16m$

Initial velocity, ${\overrightarrow{v}}_i=6\hat{i}+8\hat{j}$ and final velocity, ${\overrightarrow{v}}_f=6\hat{i}-8\hat{j}$
change in momentum $=\overrightarrow{\Delta }p=m({\overrightarrow{v}}_f-{\overrightarrow{v}}_i)=-16m\hat{j}$
$\left|\Delta p\right|=16m$