# Problem: A subatomic particle called the pion has a measured lifetime of 4.4x10-8 s. If the lifetime of a pion measured at rest is 2.6x10-8 s, how fast is the pion moving in the lab frame?

###### Problem Details

A subatomic particle called the pion has a measured lifetime of 4.4x10-8 s. If the lifetime of a pion measured at rest is 2.6x10-8 s, how fast is the pion moving in the lab frame?