## Lecture 1: Course Overview and Problem-Solving Techniques

August 22, 2017

• Study: Ex 1.1

### Objectives

• (Continuing objective throughout PHYS 211, PHYS 212, and your entire life.) Write solutions to problems with sufficient detail (i.e., show your work) so that other people can understand your approach.
• Convert from one set of units to a different set of units.
• Check answers to problems to see if they have the correct dimensions.
• Use ratios to solve quantitative problems. Specifically, use ratios and Kepler's Third Law to relate the periods and semi-major axes of objects rotating around a common planet or star.

### Homework

• Wednesday's Assigned Problems: A80, A82, A84, A85; CH 1: 27, 43

Notes: For CH 1 #43, you can assume that the surface area of the US is around 10 million square km or $1.0 \times 10^{13}\,\text{m$^2$}$. Also, FYI, there are about 300 million people in the US.

• Monday's Hand-In Problems: A4, A81, A83, A86, A87; CH 1: 26; CH 2: 14, 20, 24, 46

### Question to ponder

When you think about it, you are just borrowing those atoms for about a century or so, but they have been around for 15 billion years (and not all of that time on the planet Earth). I like to imagine a movie that could somehow follow the entire 15 billion year existence of one of these atoms -- sped up, of course. (Are there any movie majors in this course? This would be really cool to do!)

### Pre-Class Entertainment

• Ana Ng, by They Might be Giants
• Ashes to Ashes, by David Bowie
• Awkward, by San Cisco
• Ain't No Sunshine, by Bill Withers
• Ain't No Rest for the Wicked, by Cage the Elephant
• All I Wanna Do, by Sheryl Crow