College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 25

The average lifetime of a pi meson in its own frame of reference (i.e., the proper lifetime) is 2.6 × 10 8 s. If the meson moves with a speed of 0.98 c , what is (a) its mean lifetime as measured by an observer on Earth, and (b) the average distance it travels before decaying, as measured by an observer on Earth (c) What distance would it travel if time dilation did not occur