Hi, I was researching the force required to spin a space ship. There is an old thread here but I'm not quite understanding the post. https://www.physicsforums.com/archive/index.php/t-151000.html To move a spaceship forward we have something like F = ma. 1000 kilogram space ship 100 meters in length Assume a cylinder shape 30 m/s of acceleration F = 1000 x 30 = 30,000 newtons The old post talks about the Moment of Inertia He also provides a link to the moment of http://en.wikipedia.org/wiki/List_of_moments_of_inertia where if we assume our spaceship is a cyclinder like a wire. I = (m * L^2)/12 So what is the force formula to rotate the ship at 30 meters per second give the same spaceship listed above, assuming that we can put perpendicular thrusters at the very tips of the ship? I don't quite understand how torque and moment of intertia help me calculate how powerful of engines spin it at a desired rate? thanks!