1. The problem statement, all variables and given/known data This is an extract of a very long question. The electron is moving relative to the lab at 0.98c. In the reference frame of the electrons, calculate the time required for an electron to travel the length of a beam pipe which has a proper length of 100 m measured in the laboratory reference frame. 2. Relevant equations t'=y(t-vx/c^2) where y=1/(1-v^2/c^2)=6 in this case 3. The attempt at a solution The correct answer is 0.34microsecond, strangely it is, the time interval observed by a person in the lab's reference frame is also ∂t=L0/0.98c=0.34microsecond. Can someone explain to me why this is?