Question
A neutral $\pi$-meson is a particle that can be created by accelerator beams. If one such particle lives $1.40 \times 10^{-16} \textrm{ s}$ as measured in the laboratory, and $0.840 \times 10^{-16} \textrm{ s}$ when at rest relative to an observer, what is its velocity relative to the laboratory?
$2.40 \times 10^8 \textrm{ m/s}$
Solution Video