An unstable high-energy particle is created in the laboratory, and it moves at a speed of 0.991c. Relative to a stationary reference frame fixed to the laboratory, the particle travels a distance of 3.12 x 10^-3 m before disintegrating. What is
(a) the proper distance and
(b) the distance measured by a hypothetical person traveling with the particle? Determine the particle's
(c) proper lifetime and
(d) its dilated lifetime.