Let's say we put a human in a closed chamber which is going around a certain point at distance d from its center of mass at some angular velocity w. The centrifugal force on a human will be w squared over r times his mass. Is there any difference if the cause of this rotation is precession of a gyroscope connected to the chamber?enter image description here

  • $\begingroup$ It is unclear what you are asking. You seem to be mixing the effects of orbital motion with that of rotation. The short answer is that if the center of mass is not moving in a straight line, there must be a force that causes that. Can you elaborate a little more on the setup (maybe include a sketch) and describe the DOF that drive the kinematics of the system. $\endgroup$ – ja72 Mar 8 at 17:45
  • $\begingroup$ Doesnt matter what force. Of course there is a force. Do you not know what precession is? $\endgroup$ – Schaurberger Mar 8 at 18:01
  • $\begingroup$ In my mind precession is the slow rotation of the instantaneous rotation axis when it is not parallel to one of the principal rotation axes. $\endgroup$ – ja72 Mar 8 at 18:51
  • $\begingroup$ Yes. Slow relative to the rotation right? So doest really rave to be slow. I added a picture. $\endgroup$ – Schaurberger Mar 8 at 19:13
  • $\begingroup$ So if you fix a reference frame at the end of the gyroscope, and the frame is not itself rotating, only precessing, how many Gs of force will the person inside feel? $\endgroup$ – Schaurberger Mar 8 at 19:14

A reference frame rotating at the rate of a precessing gyroscope is still a rotating reference frame. It is not inertial. All of the usual effects in a rotating reference frame will be present including the usual centrifugal force.

  • $\begingroup$ I do not think so. There should be according to newstons laws. But I don't think there is $\endgroup$ – Schaurberger Mar 9 at 16:41
  • $\begingroup$ So which of Newton’s laws do you think is wrong in this case and exactly how do you think it fails? $\endgroup$ – Dale Mar 9 at 17:58
  • $\begingroup$ No single one, Newtons laws don't work in all frames of reference all by them selves , to make the theory work you need to add some "inertial " forces. In this case there seems to be a contradiction with the Newtonian mechanics as you are in an accelerating frame and there at least in my opinion should be no inertial forces present. $\endgroup$ – Schaurberger Mar 9 at 19:26
  • $\begingroup$ There are inertial forces in this frame, specifically the centrifugal and the Coriolis forces. $\endgroup$ – Dale Mar 9 at 20:12
  • $\begingroup$ Have you ever seen a gyroscope precessing on a toy Eiffel tower as a pivot? $\endgroup$ – Schaurberger Mar 9 at 20:31

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.