Suppose a recently found elementary particle has an average life time, T = 10.6 ns, when at rest. For instance, a charged pion has a lifetime Tpi ± =26.030 ns. The pion normally decays into a muon and a neutrino: π+ →µ+ + νµ.
In order for this new elementary particle to travel 7 m in one life time, find how fast must it be moving relative to the velocity of light?