## Lecture 25: Curved Space and Gravity

December 5, 2017

### Objectives

• (Continuing objective) Relate the concepts of rotational motion and gravity to “everyday” situations and discuss various applications of the concepts to practical problems in various fields of science, medicine and engineering.
• Determine the rates for stationary clocks in the presence of a spherical mass according to Einstein's theory of general relativity.
• Describe Einstein's “Equivalence Principle” and explain how it predicts the bending of light by a gravitational body.
• Measure or calculate distances between circles on a surface or in space, and use these results to determine if the surface or space is flat or curved.

### Homework

• Assigned Problems: A65, A88; Supp CH 11: 1, 2, 5

Highlight the white space below with your mouse to see the answers for A88:

The four physics errors in the story in A88 are: (1) The Enterprise can't be going at a speed of 7 times the speed of light relative to anything; (2)there is no way that Picard and Janeway could be having this kind of conversation without significant delays, due to the time that it takes for radio signals to travel 5 light years (i.e., it would take 10 years to get any response); (3) adding another ice cube won't cause any reduction in temperature for Picard's tea, since it is already at a temperature of $0^{\circ}$C; (4) when the torpedo destroys the engines of the Enterprise, the ship won't stop'' (whatever that is supposed to mean out in space) -- it will continue at the same velocity.

Notes: There is no problem session associated with the last lecture.

### Pre-Class Entertainment

• Walking on the Sun, by Smash Mouth
• What I Got, by Sublime
• Wicked Game, by Chris Isaak
• Wish I Knew You, by the Revivalists
• The Walker, by Fitz and the Tantrum
• Waves, by Blondfire