Group problems: 32. 19 You may wish to wait until after class Monday before starting the following problems: 33. 9

Physics 106b – 2014 Assignment 10
Due: Friday, 4-25-14, 4:00 pm

Reading: Ch. 33, “Relativity Fundamentals Explained Well” document
Assigned exercises:
Mastering Physics Problem Set 10, plus the handwritten problems below
Individual problems:

32.61
Group problems:
32.19

You may wish to wait until after class Monday before starting the following problems:

33.9

10A. The Andromeda galaxy is two million light years from Earth, measured in the rest frame of Earth and Andromeda. You are the communications officer on a fast spaceship, which takes 50 years (as measured on board ship) to get from Earth to Andromeda. As soon as you reach Andromeda, you send a radio message home. As measured by observers on Earth, approximately (to within a few percent) what is the total time between when you left Earth and when they receive your message? Explain.

10B. Observers in frame S see an explosion located at x₁ = 480 m. A second explosion occurs 5 s later at x₂ = 1200 m. In frame S’ (which moves along the +x axis), the explosions occur at the same point in space. What is the separation in time between the two explosions as measured in S’? Hint: If the explosions occur at the same place in S’, and we imagine putting an (unfortunate) observer B’ at that position, what is her speed (as measured in S) ?

You should also continue working on your creative project. I have allocated about 3 hours from the current assignment for you to work on it this week.