tag:blogger.com,1999:blog-5376628436133716219.post3179098596077908776..comments2024-03-27T20:33:20.382-07:00Comments on Why I hate physics: Again with the rotor barsMarty Greenhttp://www.blogger.com/profile/17624084719249673373noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-5376628436133716219.post-13392620905479023222013-01-26T04:00:00.142-08:002013-01-26T04:00:00.142-08:00This is a very promising argument but I am unable ...This is a very promising argument but I am unable to personally verify the integration. I agree there ought to be a way of analyzing it as a field-on-field interaction, but I still find it very odd that you should not get the same result by alternatively analyzing by ILxB. Shouldn't they both give the same answer?Marty Greenhttps://www.blogger.com/profile/17624084719249673373noreply@blogger.comtag:blogger.com,1999:blog-5376628436133716219.post-29884312566198679882013-01-25T10:57:38.213-08:002013-01-25T10:57:38.213-08:00Marty,
The current does not need to interact with ...Marty,<br />The current does not need to interact with a surrounding magnetic field to generate a force. <br /><br />A moving charge in a magnetic field does not generate a force. I know , I know we are told F=q(uxB), but what is qu? A current. Remember:<br /> J = delxH.<br /> Thus we can see that:<br /> F=(delxH)xB.<br />Were H is the field generated by the moving charge and B is the surrounding field density. <br /><br />So in the rotor bars it isn't the electrons interacting with the external magnetic field, but the magnetic field they are generating that is interacting with the external field. <br /><br />The magnetic field generated by a wire carrying a current is:<br /> <b>uI/(2PIr),</b><br />where r is the distance from the wire. So the force per unit length of wire is going to be:<br /> <b>F = ((delx(uI/2PIr))xB)dl </b>. <br />Thus integrating over l you get:<br /> F= L*uI*B/(2PIr).<br />This is why the formula: F = ILxB gives the right answer even though physically the electronics don't pass through field.Johnnoreply@blogger.com