Why do things rotate? I know what torques are.....the question is deeper than that... This is not any homework or coursework problem. This question has been troubling me since it first popped into my head. Suppose there are two point masses both of mass m, connected to each other by a massless rigid rod. Suppose we have the rod in a horizontal position in gravity free sapce. Now a force , F, is applied to the right mass(could be left mass too) in the forward direction. Now according to the newton's laws, the entire system should have a linear acceleration of F/2m. So, both the balls move ahead with a=F/2m, to say the least. So far so good. I read in some book a long time back that the concepts of torque and angular momentum are not independent laws of nature, and that they have been derived from the more fundamental newton's laws of motion. That means, that the rotational motion is simply a manifestation of the newton's laws. If it is really so, then in the above example of two masses, why does the system of these two masses also rotate along with moving forward with a linear acceleration ,a=F/2m ? The two masses, apart from having a forward component of acceleration, a=F/2m, which was derived from the newton's laws, also have another component of acceleration, namely, the angular acceleration. Where did this new component of acceleration, i.e. the angular acceleration come from? Please explain how the newton's laws gave rise to this angular acceleration component? P.S. Please don't use the concepts of torques and angular momentum. I want an answer purely in terms of Newton's laws. If the torques are really not independent laws of nature, and if rotation is really a manifestation of the newton's laws, there should be an answer to the above in terms of newton's laws.