The discussion revolves around calculating the effects of applied force on a box, specifically how much of that force contributes to rotational motion versus translational motion. The scope includes theoretical considerations of torque and force application in a physics context.
Participants express differing views on the feasibility of achieving rotation without translation, with some suggesting that it is impossible with a single force while others explore the concept of using multiple forces.
There are unresolved aspects regarding the specific calculations of torque and force distribution, as well as the conditions under which pure rotation can be achieved, which depend on the definitions and assumptions made about the forces involved.
The entire force goes into accelerating the center of mass, per Newton's 2nd law, regardless of where on the box you exert that force. That same force will also exert a torque about the center of mass, which will tend to turn the box. The amount of torque you get depends on the angle the force is applied and its distance from the center of mass.DrSammyD said:If I push forward on a box at a certain position, how do I calculate how much force will go into turning it, and how much force will go into moving it forward since it's not fixed to a position.
Doc Al said:The entire force goes into accelerating the center of mass, per Newton's 2nd law, regardless of where on the box you exert that force. That same force will also exert a torque about the center of mass, which will tend to turn the box. The amount of torque you get depends on the angle the force is applied and its distance from the center of mass.
There's no way to exert a single force and only get rotation. What you might want to do is exert a couple of forces--two equal forces in opposite directions. The net force will be zero, but the net torque will not be zero.DrSammyD said:Then I guess what I'm asking is, How much force do I have to push, where, and in what direction in order to have the box not move other than rotation.