Question

which component of torque will be zero :

1. along an axis ??

2. w.r.t. a point

also explain why , with suitable examples(if possible) ??

Answer 1

We know that the torque is given by the cross product of the applied force and the radius vector joining the point of application of force to the point about which the torque needs to be computed.
Radial component of force passes through the line joining the point of application of force and the point about which the torque needs to be computed.
The angle between them is 0, and hence the cross product is also zero. Thus torque will also be zero.
For transversal component, angle is 90 degree.
i.e. sinθ = 1
Therefore, torque is only due transverse component of force, radial component of torque is zero.