Question

The work done by the force $(4,-2,3)$ to move a particle along a straight line from the point $A(3,3,-1)$ to $B(6,4,-2)$ is

• A. 3 units
• B. 5 units
• C. 7 units
• D. 9 units

Answer 1

The correct option is C 7 units

We know that work done by given force is calculated as $W=\overrightarrow{F.}\overrightarrow{S}$
So first calculating the vector S, which can be calculated as

$\overrightarrow{S}=\left(\overrightarrow{B}-\overrightarrow{A}\right)\Rightarrow \overrightarrow{S}=\left(6-3\right)\hat{i}+\left(4-3\right)\hat{j}+\left(-2-\left(-1\right)\right)\hat{k}\Rightarrow \overrightarrow{S}=3\hat{i}+\hat{j}-\hat{k}$
$W=\overrightarrow{F.}\overrightarrow{S}=(4\hat{i}-2\hat{j}+3\hat{k}).(3\hat{i}+\hat{j}-\hat{k})=7\mathrm{units}$
So, option C is correct answer.