Reading Questions for Boynton, Chapter 15, and Zee Chapters 1, 2, & 3

Due February 4 ( worth 10 participation points!)

1. Boynton, Chapter 15

1. Page 89 of Boynton is a bit hard to understand, especially the points being made about Sir Isaac Newton's viewpoints on frames of rest, inertia, and acceleration. Please summarize your interpretation of Newton's viewpoints.
2. In your own words, what does the equivalence of the gravitational mass and the inertial mass mean?
3. What is the The Eöt-Wash Group (http://www.npl.washington.edu/eotwash/index.html) attempting to do here at the University of Washington? (Their work will be referenced when we discuss gravitational waves, so this is an important link to check out.)
4. Contrast Newton's picture of the force of gravity to Einstein's view (where there is no force of gravity).
5. What did you not understand about the logic that leads to the conclusion that light is bent by gravity?

2. Zee, Chapter 1 - 3

• Height of Mt. Everest: 8,848 meters
• Height of low-orbit satellite: 405,000 meters
• Radius of Earth: 6,378,000 meters; mass = 5.974× 10²⁴ kilograms
• , where here R will represent the distance from the center of the Earth; g = 9.8 m/s² on Earth's surface

1. Certainly climbers at the top of Mt. Everest feel the acceleration due to gravity: g = 9.77 m/s² way up there. If the astronauts in the International Space Station were to suddenly stop, they would be subjected to the acceleration due to the Earth's gravity: g = 8.66 m/s² (using the above numbers and formula to calculate.) But, wait! The Earth doesn't "know" whether the Space Station is moving or not, so why doesn't it crash down to the ground?
2. Explain why the concept of a gravitational field is more convenient for scientists than stating that a body with mass exerts a gravitational force.
3. How does the equivalence principle lead to the idea that gravity bends light?
4. Interpret the equation E = mc² using words and explain how this equation implies that a black hole is inevitable under certain conditions.
5. What is a graviton and how does it fit into Einstein's theory of gravity?

Since it took Einstein 10 years to come up with parts of his theory, and there are other parts that still are not solved, it is not necessary that we completely understand even from a qualitative point of view all that Prof. A. Zee talks about. But, hopefully it is kind of fun to think about.