1. The problem statement, all variables and given/known data An excited nucleus of krypton-80 emits a gamma ray that travels at the speed of light relative to the nucleus. The nucleus itself has a speed of 0.60c relative to the sun. Use a relativistic velocity transformation to determine the speed of the gamma ray relative to the sun if the gamma ray is emitted: a) in the direction of motion of the nucleus and b) opposite to the direction of motion of the nucleus 3. The attempt at a solution a) u = u' + v / 1 + vu'/c^2 u = 1 + 0.6 / 1 +(0.6)(1)/c^2 u = 1 c Does this make sense? Can a particle not move faster then the speed of light? b) Not sure how to approach this! would a number be negative?