I made up this problem, on two ends of an uniform stick AB there acts two parallel & like forces of $15N$ and $35N$(on A and B respectively). So there is resultant force of 50 N and it acts on point P which is $15/35$ m away from B.
As the resultant force doesn't work on the COM, the stick will spin.
The problem is how to measure the torque in this case. There seems to be no fixed axis relative to which the stick is spinning.
Any hint on this regard?