Let S and S' be inertial frames. Frame S' moves at velocity v with respect to frame S in the common (positive) x-direction. Measurements of events in the two frames, denoted respectively by (x, y, z, t) and (x', y', z', t'), are related by the Lorentz transformation:
x' = ̳(x - vt), y' = y, z' = z, t' = ̳(t - (v/c^2)x)
where ̳ = 1/sqrt(1-v^2/c^2) and c is the speed of light.
(a) Show that the quantity (x'^2 - c^2t'^2) is invariant under this Lorentz transformation.
(b) By algebraically solving for x and t, find the inverse Lorentz transformation, i.e., express (x, y, z, t) in terms of (x', y', z', t').
(c) Explain why you could have expected this result, based on the velocity of frame S relative to frame S'.
Question 2
Consider inertial frames S and S'. Frame S' moves at velocity v with respect to frame S in the common (positive) x-direction. Measurements of an event in two frames (x, y, z, t) and (x', y', z', t') are related by the Lorentz transformation:
x' = ̳(x - vt), y' = y, z' = z, t' = ̳(t - (v/c^2)x)
where ̳ = 1/sqrt(1-v^2/c^2) and c is the speed of light.
(a) A photon has velocity u' = (0, 0, c) relative to frame S' where u' = (u'_x, u'_y, u'_z). Find the velocity, u, of the photon relative to frame S.
(b) Explain how your result is consistent with the constancy of the speed of light.