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Physics/Magnetic Force


Hi, I have a question concerning a video I saw in YouTube ( about a magnetic rail gun. In these video two students build a magnetic rail gun putting two parallel lines of rectangular magnets horizontally at 45 degrees.  Then they insert “push” one small magnet (projectile) at the beginning between the two lines of magnets and the small magnet (projectile) was expelled from the other end.
My first question: Does the force applied to the projectile (to enter in the track) is equal to the force that the projectile is repelled?
What happen if I rotate the horizontal plan of the rail gun track to 60 degrees (for example). Does the projectile will be expelled? The force will be sufficient to expel the projectile?
Thank you

1st Q: no.  The total energy expressed in the projectile acceleration is matched by the energy pushing the opposite direction on the gun.

2nd Q: possibly.  The total acceleration would have to overcome some of gravity and friction associated with the track in the gun.

Just watching the two young investigators in the video, I would guess yes.

A nice little explanation of the forces generated can be found here:

Depending on your math level, it may be all the info you need.

Take care!


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Dr. Jeffery Raymond


Materials chemistry. Materials science. Spectroscopy. Polymer science. Physical Chemistry. General Physics. Technical writing. General Applied Mathematics. Nanomaterials. Optoelectronic Behavior. Science Policy.


Teaching: General Inorganic Chemistry I & II, Organic Chemistry I & II, Physical Chemistry I, Polymeric Materials, General Physics I, Calculus I & II
My prior experience includes the United States Army and three years as a development chemist in industry. Currently I am the Assistant Director of the Laboratory for Synthetic Biological Interactions. All told, 13 years of experience in research, development and science education.

Texas A&M University, American Chemical Society, POLY-ACS, SPIE

Journal of the American Chemical Society, Nanoletters, Journal of Physical Chemistry C, Journal of Physical Chemistry Letters, Ultramicroscopy Proceedings of SPIE, Proceedings of MRS, Polymer News, Chemical and Engineering News, Nano Letters, Small,, Angewandte

PhD Macromolecular Science and Engineering (Photophysics/Nanomaterials Concentration), MS Materials Science, BS Chemistry and Physics, Graduate Certificate in Science Policy, AAS Chemical Technology, AAS Engineering Technology

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