A particle known as a pion lives for a short time before breaking apart into other particles. Suppose a pion is moving at a speed of 0.990c, and an observer who is stationary in a laboratory measures the pion's lifetime to be 2.8 x 10-8 s. (a) What is the lifetime according to a hypothetical person who is riding along with the pion? (b) According to this hypothetical person, how far does the laboratory move Before the pion breaks apart? (a) Number (b) Number i Units Units

1. You are an observer in a 100-m long spacecraft traveling from the earth to the moon at 0.8c. (a)What is the proper length of the spacecraft? (b) For a proper time interval of 1 sec., the relativistic time interval for the spacecraft measured from the earth reference frame would be: (c)Time dilation does not apply to all time-dependent physical and biological processes. T/F? (c) What is the relativistic length, DL measured from the reference frame of earth? (d) An APOLLO crew left a flat mirror reflector on the surface of the moon (for all you deniers out there, in the 50th anniversary year of APOLLO 11!). If the average surface-to-surface distance from the earth to the moon is 3.83 x 10^8 m, then how long does it take moonlight to reach earth?

A particle whizzes through your lab at a speed of 0.74c. Your detectors determine that its lifetime was 1.1ns. Find its lifetime in the particle's reference frame. Please give your answer in nanoseconds.

The distance from earth to the center of our galaxy is about 33,000 ly (1 ly = 1 light year = 9.47 x 1015 m), as measured by an earth- based observer. A spaceship is to make this journey at a speed of 0.9990c. According to a clock on board the spaceship, how long will it take to make the trip? Express your answer in years. (1 yr is equal to 3.16 x 107 s.) Number i d Modic Units