Question

A small particle moves to position $5 \hat{i}-2 \hat{j}+\hat{k}$ from its initial position $2 \hat{i}+3 \hat{j}-4 \hat{k}$ under the action of force $5 \hat{i}+2 \hat{j}+7 \hat{k} N$. The value of work done will be ________$J$

Answer 1

$W=\vec{F}.(\vec{r_{f}}-\vec{r_{i}})$

$=(5\widehat{i}+2\widehat{j}+7\widehat{k}).((5\widehat{i}-2\widehat{j}+\widehat{k})-(2\widehat{i}+2\widehat{j}-4\widehat{k}))$

$W=40J$

So, The correct answer is 40.