Magnetic Field Force: Attraction & Repulsion

[nemesiswes]

I was wondering what, if you had two electromagnets and normaly when you turn them on they would cause a force on the other ( attractive or repelling ) but if you were to pulse each one so fast that the they would turn off before the magnetic field reached the other , then would that still cause a force on both since there both electromagnets. if they don't then wouldn't that violate some law because by turning them off then wouldn't that mean the information that they are now off gets to the object before the intial wave got there.

 

[zodas]

Well ! What I think is
Magnetic field moves at a speed of light.So, in order to turn off before causing a force,you must move your hand at a faster speed than light.
But acc. to Einstein's theory of relativity ,it is not possible

 

[newbee]

There would still be a force on both. Coil 1 will emit a EM pulse that will, by Faradays Law, induce an electric field within Coil 2 and therefore a current in Coil 2. The current carrying Coil 2, by the Lorentz Force Law, experiences a force as it interacts with the traveling EM pulse.