Two Observers and the Motion of Protons

[tomz]

hello, this is a question from the book that i got no idea on it

'When two proton are traveling at same velocity parallel to each other, like this (respect to groung)

proton A >>>
proton B >>>

an observer is also travel at the same speed along their path. according to him, two proton are stationary, so the only force is the electrical attraction

Another observer who is stationary will observe two proton moving, both create magnetic field which influence the motion of the other proton

What do you say?

I thought the two observer are both in inertial frame, therefore should applied the same law. but the situation is different to that? i am totally confused.

Can anyone help me? thanks very much

 

[hzq]

I think it's that the time interval is also different,so the effect of the electric force is defferent.You can calculate it.