If \(\vec{F}\) is the force acting on a particle having position vector \(\vec{r}\) and \(\vec{\tau}\) be the torque of this force about the origin, then:
Answer & explanation
Correct answer: option 2
\(\vec{\tau} = \vec{r} × \vec{F}\)
\(\tau\) is ⊥ to both \(\vec{r}\) and \(\vec{F}\)
⇒ \(\vec{r} . \vec{\tau} = 0\)
\(\vec{F}.\vec{\tau}=0\)