Let vec(F) be the force acting on a particle having position vector vec(r ) and vec(tau) be the torque of this force about the origin. Then

Let vec(F) be the force acting on a particle having position vector ve

1.	Let vec(F) be 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» `vec(r ).vec(F)=0` and `vec(r ).vec(tau)NE0` `vec(r ).vec(tau)ne0` and `vec(F).vec(tau)=0` `vec(r ).vec(tau)ne0` and `vec(F).vec(tau)ne0` `vec(r ).vec(tau)=0` and `vec(F).vec(tau)=0` ANSWER :D