Question

A body constrained to move along the z-axis of a coordinate system is subject to a constant force F given by F = -$\hat{i}$ + 2$\hat{j}$ + 3$\hat{k}$ N where $\hat{i}$, $\hat{j}$, $\hat{k}$ are unit vectors along the x-, y- and z-axis of the system respectively. What is the work done by this force in moving the body a distance of 4 m along the z-axis ?

Answer 1

Given

F = $-\hat{i}+2\hat{j}+3\hat{k}$ N

Work done is given by,
$W=\overrightarrow{F}.\overrightarrow{s}$
$W=(-\hat{i}+2\hat{j}+3\hat{k}).\left(4\hat{k}\right)=12J$