Let F be the force acting on a particle having position vector r vector and T vector be the torque of this force about the origin. Then
(a) r vector X T vector=0 and F vector X T vector =0
(b) r vector X T vector = 0 and F vector x T vector not equal to Zero
(c) r vector X T vector not equal to zero and F vector X T vector = 0
(d) r vector x T vector not equal to zero and F vector x t vector not equal zer0
Ans.a
(9)