Question

The direction of vector $\vec{A}$ is reversed. What are the values $\Delta \vec{A}$ and $\Delta |\vec{A}|?$

• A. $+2\vec{A},0$
• B. $+\vec{A},0$
• C. $-\vec{A},0$
• D. $-2\vec{A},0$

Answer 1

Answer: (D)

When direction of a vector is reversed it has same magnitude but -with minus sign.
The value of $\Delta \vec{A}={\vec{A}}_2-{\vec{A}}_1$
Given, ${\vec{A}}_1=,A,{\vec{A}}_2=-A$
$\therefore$ $\Delta \vec{A}=-A-A=-2\vec{A}$
Also, $|\vec{A}|=|-\vec{A}|$
$\therefore \Delta |\vec{A}|=0$