- #1

answerseeker

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how fast must a pion be moving, on average, to travel 10m before it decays? average lifetime is 2.6*10^-8.

i know the answer is D=V( to/ sqroot 1-v^2/c^2) but i don't understand why and how to know when to put the time expansion equation into the D=vt equation.

When would u ever do this again, and why isn't the pion's lifetime= t, b/c its at rest.