Question

$A$ force $\overrightarrow{F}=2\hat{i}+4\hat{j}+\hat{k}$ acts on a body and produces a displacement of $\overrightarrow{S}=3\hat{i}+2\hat{j}+5\hat{k}$. Work done is:

• A. 10 units
• B. 19 units
• C. 29 units
• D. zero

Answer 1

The correct option is B 19 units

$W=\overrightarrow{F}\cdot \overrightarrow{S}\overrightarrow{F}=2\hat{i}+4\hat{j}+\hat{k}\overrightarrow{S}=3\hat{i}+2\hat{j}+5\hat{k}\Rightarrow W=2\times 3+4\times 2+1\times 5=19units$