- #1
Happiness
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Suppose frame ##S^\prime## moves in the positive ##x## direction at ##v## with respect to frame ##S##, and frame ##S^"## moves in the positive ##y## direction at ##v^\prime## with respect to frame ##S^\prime##.
Then,
##E^\prime_x=E_x##
##E^\prime_y=\gamma(E_y - vB_z)##
##E^\prime_z=\gamma(E_z + vB_y)##
and
##E^{\prime\prime}_x=\gamma^\prime(E^\prime_x+v^\prime B^\prime_z)##
##E^{\prime\prime}_y=E^\prime_y##
##E^{\prime\prime}_z=\gamma^\prime(E^\prime_z-v^\prime B^\prime_x)##
Substituting the first set of equations into the second set, we have
##E^{\prime\prime}_x=\gamma^\prime(E_x+v^\prime B^\prime_z)##
##E^{\prime\prime}_y=\gamma(E_y-vB_z)##
##E^{\prime\prime}_z=\gamma^\prime[\gamma(E_z + vB_y)-v^\prime B^\prime_x]##
With respect to frame ##S##, frame ##S^"## would not move in the positive ##x## direction but at angle ##\theta## anticlockwise from the positive ##x## direction at a velocity ##v_0##.
Let ##x_0## be the axis pointing in the direction of ##v_0##.
Then,
##E^"_{x_0}=E^"_x\cos\theta+E^"_y\sin\theta=\gamma^\prime\cos\theta\ (E_x+v^\prime B^\prime_z)+\gamma\sin\theta\ (E_y-vB_z)##
But
##E_{x_0}=E_x\cos\theta+E_y\sin\theta\neq E^"_{x_0}##
We have a contradiction.
Then,
##E^\prime_x=E_x##
##E^\prime_y=\gamma(E_y - vB_z)##
##E^\prime_z=\gamma(E_z + vB_y)##
and
##E^{\prime\prime}_x=\gamma^\prime(E^\prime_x+v^\prime B^\prime_z)##
##E^{\prime\prime}_y=E^\prime_y##
##E^{\prime\prime}_z=\gamma^\prime(E^\prime_z-v^\prime B^\prime_x)##
Substituting the first set of equations into the second set, we have
##E^{\prime\prime}_x=\gamma^\prime(E_x+v^\prime B^\prime_z)##
##E^{\prime\prime}_y=\gamma(E_y-vB_z)##
##E^{\prime\prime}_z=\gamma^\prime[\gamma(E_z + vB_y)-v^\prime B^\prime_x]##
With respect to frame ##S##, frame ##S^"## would not move in the positive ##x## direction but at angle ##\theta## anticlockwise from the positive ##x## direction at a velocity ##v_0##.
Let ##x_0## be the axis pointing in the direction of ##v_0##.
Then,
##E^"_{x_0}=E^"_x\cos\theta+E^"_y\sin\theta=\gamma^\prime\cos\theta\ (E_x+v^\prime B^\prime_z)+\gamma\sin\theta\ (E_y-vB_z)##
But
##E_{x_0}=E_x\cos\theta+E_y\sin\theta\neq E^"_{x_0}##
We have a contradiction.