Problem set 3 for ASTR 204: Einstein's Universe

Due in class Thurs October 11

Bennett Ch S-4 Problems 1, 2, 3, 4, 5

(6) By researching on the web or elsewhere, find out and write a 2-3 paragraph description of how the GPS (Global Positioning System) works, and what relativistic corrections are needed to make it work accurately.

(7) Read the description of Jules Verne's A Trip from the Earth to the Moon in the handout (or read the book!). Does his description of the abrupt change in the direction of gravity at the point where the pull of the Earth and Moon are equal agree with your intuitions? Explain why you think your intuitions are the same or different from Verne's. Using this example, explain why a person in free fall, in a falling elevator or a spaceship, does not feel the force of gravity, even though they are still in a gravitational field.

Group question (1):

Imagine that you are part of a team playing your favorite game (softball, football, basketball) in a different universe where the speed of light is 100 miles/hr (very roughly the fastest speed that a ball can be thrown on Earth). Write 1-2 pages describing how the game will differ from the one you are used to.

Group question (2):

Bennett Ch S-4 Problem 7.

To give you time to find and watch the movie, this part of the homework is due Thursday October 18.