Question

If force $\overrightarrow{F}=5\hat{i}+3\widehat{kj}+4\hat{k}$ makes a displacement of $\overrightarrow{s}=6\hat{i}-5\hat{k}$, work done by the force is

• A. $10unit$
• B. $122\sqrt{5}unit$
• C. $5\sqrt{122}unit$
• D. $20unit$

Answer 1

The correct option is A $10unit$

We know that

Work done $=force\times displacement$

Work done $=\left(5\hat{i}+6\hat{j}+4\hat{k}\right)\cdot \left(6\hat{i}+0\hat{j}-5\hat{k}\right)$

Work done$=30-20=10$ $unit$

Hence,

option $\left(A\right)$ is correct answer.