The average lifetime of a pi meson in its own frame of

Question

The average lifetime of a pi meson in its own frame of reference (i.e., the proper lifetime) is 2.6 10-8 s.

(a) If the meson moves with a speed of 0.90c, what is its mean lifetime as measured by an observer on Earth?

s

(b) What is the average distance it travels before decaying, as measured by an observer on Earth?

m

(c) What distance would it travel if time dilation did not occur?

m