This is about a little thing that I have a lot of trouble understanding, and which always bugs me when studying equilibrium. I've often tried to apply the concepts of torque in this context, but nothing ever seems to make sense. I consider a uniform rod which is initially at rest, and is not pivoted to any point by anything, to suddenly be acted upon by a force (or forces) - impulsive or otherwise - not passing through it's center of mass in a single plane. The center of mass of the rod should accelerate according to the net force acting on the rod in that plane. But I have a lot of trouble understanding how the rod would rotate, i.e., about which axis it would rotate. I'll break down my question by taking two cases here: 1. The first case is when the net of the forces is zero. I'm assuming the rotation axis would then be through the center of mass, because it is at rest (right?). 2. Now, this second case gets me really confused: what if the net of the forces is not zero?? What would be the rotation axis then. I tried assuming the rotation axis would be the one about which the net torque is zero, and I applied that idea in some questions, but they all went wrong...... Please help. Thank you.