There are relativistic formulas for adding relative velocities. You need to learn them.
(a) In Earth-fixed coordinates, the bullet fired forward has a velocity
(0.79c + 0.92c)/[1 + (0.79c*0.92c/c^2]
= 1.710c/1.727 c = 0.990c
(b) In Earth-fixed coordinates, the bullet fired backwards has velocity
(0.79c - 0.92c)/[1 + (0.79c*0.92c/c^2]
= -0.13/1.727 c = -0.075c
The minus sign means it is going backwards relative to the space ship.
A rocket cruising past Earth at 0.79c shoots two bullets at 0.92c relative to the rocket with one of the bullets fired along the direction of the rocket's motion and the other fired opposite the rocket's motion.
(a) What velocity does an Earth-based experimenter measure for the bullet fired in the direction of motion of the rocket? Give your answer as a fraction of c, where positive values are used if the velocity is in the same direction of the ship.
(a) What speed does an Earth-based experimenter measure for the bullet fired in the direction of motion of the rocket? Give your answer as a fraction of c, where positive values are used if the velocity is in the same direction of the ship.
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