A cosmic ray particle travels directly over a football field, from one goal line to the other, at a speed of 0.454c.
a. If the length of the field between goal lines in the Earth frame is 91.5 m, what length is measured in the rest frame of the particle?
b. How long does it take the particle to go from one goal line to the other according to Earth observers?
c. How long does it take in the rest frame of the particle?