Question

If force $\overrightarrow{F}=(15\hat{i}+60\hat{j}-3\hat{k})N$ and velocity $\overrightarrow{v}=(-4\hat{i}+2\hat{j}+5\hat{k})$ m/s, then instantaneous power is

• A. 195 W
• B. 45 W
• C. 75 W
• D. 100 W

Answer 1

The correct option is A 195 W

Given that ,

Force , $\overrightarrow{F}=(15\hat{i}+60\hat{j}-3\hat{k})N$

Velocity , $\overrightarrow{v}=(-4\hat{i}+2\hat{j}+5\hat{k})m/s$

Instantaneous power , $P=\overrightarrow{F}\cdot \overrightarrow{v}=-60+120-15=45W$