Observer A, who is at rest in the laboratory, is study- ing a particle that is moving through the laboratory at a speed of 0.624c and determines its lifetime to be 159 ns. (a) Observer A places markers in the laboratory at the locations where the particle is produced and where it decays. How far apart are those markers in the labo- ratory? (b) Observer B, who is traveling parallel to the particle at a speed of 0.624c, observes the particle to be at rest and measures its lifetime to be 124 ns. Accord- ing to B, how far apart are the two markers in the laboratory?

Observer A, who is at rest in the laboratory, is study- ing a particle that is moving through the laboratory at a speed of 0.624c and determines its lifetime to be 159 ns. (a) Observer A places markers in the laboratory at the locations where the particle is produced and where it decays. How far apart are those markers in the labo- ratory? (b) Observer B, who is traveling parallel to the particle at a speed of 0.624c, observes the particle to be at rest and measures its lifetime to be 124 ns. Accord- ing to B, how far apart are the two markers in the laboratory?