Question

The work done by a force $2\hat{i}-\hat{j}+5\hat{k}$ when it displaces the body from a point (3,4,6) to a point (7,2,5) is

• A. 5 units
• B. 7 units
• C. 1 units
• D. 15 units

Answer 1

The correct option is A 5 units

Given that

Force , $\overrightarrow{F}=2\hat{i}-\hat{j}+5\hat{k}$ N

Displacement vector from $(3,4,6)$ to $(7,2,5)$ , $\overrightarrow{s}=4\hat{i}-2\hat{j}-\hat{k}$

Work done by the force , $W=\overrightarrow{F}\cdot \overrightarrow{s}=8+2-5=5J$