I have problems with some excercises before my exam on friday. plz help me 1) A charged pimeson has a lifetime of t=2,6*10^-8 s in its resting system. a) How far distance L does it travel in Inrelastvistic mechanics?If its kinetic energy is 700 MeV? b) How far distance L0 (seen by observator in laboratoriesystem) does it go by relativistik mechaniks? Pimesons mass is140 MeV/c^2. I get a to be 20 m using 700 = 1/2*mv^2 but i don't get b. Anyone that can solve it?