Question

An unstable high-energy particle is created in the laboratory, and it moves at a speed of 0.994c. Relative to a stationary reference frame fixed to the laboratory, the particle travels a distance of 1.84 × 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.

Numerical answer is not important...a) I do not understand why 1.84 x10^-3 m is the proper distance. b)Why is the distance measured by a hypothetical person traveling with the particle the Length contraction? c)How come The proper time is equal to length contraction over velocity? Please explain I do not understand, thank you so so much. :)

Answer 1