Question

The angular velocity of a body is $\overrightarrow{\omega }=2\hat{i}+3\hat{j}+4\hat{k}$ and a torque $\overrightarrow{\tau }=\hat{i}+2\hat{j}+3\hat{k}$ acts on it. The rotational power will be

• A. 20 W
• B. 15 W
• C. $\sqrt{17}W$
• D. $\sqrt{14}W$

Answer 1

The correct option is A 20 W

Power $\left(P\right)=\overrightarrow{\tau }.\overrightarrow{\omega }=(i+2\hat{j}+3\hat{k}).(2\hat{i}+3\hat{j}+4\hat{k})=2+6+12=20W$