6. One of the potentially confusing things about special relativity is that it shows us that the time measured between two events depends upon your inertial frame of reference. In particular, two events that appear to be simultaneous in one inertial frame may be measured to occur at different times in a different inertial frame. Even more interesting is that Event 1 might occur either before or after (or at the same time as) Event 2, depending upon your reference frame! The proper interpretation of these facts is to say that nothing in physics forces two simultaneous events in one frame to be simultaneous in any other frame. However, what about the order of events when Event 1 CAUSES Event 2? For example, let's consider two events from a game of pool: 1) A cue ball, traveling at 10 m/s, hits the eight ball (of mass equal to the cue ball). An elastic collision transfers all the linear momentum of the cue ball to the eight ball. 0oondc lotor the gicht bol1 10 from the collision noint

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?

1. Two atomic clocks are synchronized. One is placed on a satellite, which orbits around the earth at high speed for a whole year. The other is placed in a lab and remains at rest, with respect to the earth. You may assume that both clocks can measure time accurately to many significant digits. a. Will the two clocks still be synchronized after one year? Explain your reasoning. b. Imagine that the speed of light was much slower than its actual value. How would the results of this experiment change if the speed of light was only twice the average speed of the satellite? Explain your reasoning, using a calculation.

Answer both of the following questions regarding Special Relativity: a) An astronaut leaves their twin behind on Earth and departs on a journey on a spacecraft travelling at a speed of 0.840c. After 40.0 years pass on Earth, the astronaut returns to Earth to find that their age is now different from their twin. Both twins were 20 years old when the journey started. How old is the astronaut upon returning to Earth?