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Darrin

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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

For rotation, the equation is \tau = I \alpha which says that the torque produces an acceleration alpha, which is inversely porportional to the moment of inertia I. Just as in F=ma we are saying that the force accelerates the mass at an acceleration that is in inverse proportion to its mass. Same force, twice the mass, half the acceleration. Same torque, twice the I, half the rotational acceleration alpha.

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!