Welcome to Physics 229!

• No lab this week• Lab next week: 1. The Winter Sky• Test 1: Wednesday, 2/12.• Homework, due Wednesday, 1/29*:– Bennett, et al., Chapter 1.

Problems 44, 45, 46, 47, 58, 59 (2-3 paragraphs).*typically I’ll grade 3 of thesePlease type word answers, you can handwrite calculations.

Metric Units

• Mass – kilogram• Force – Newton• Energy – Joule• Length – meter• Time - second

Metric PrefixesPrefix Symbol Power of Ten

yocto- y 10-24

femto- f 10-15

pico- p 10-12

nano- n 10-9

micro- μ 10-6

milli- m 10-3

- -

kilo- k 103

mega- M 106

giga- G 109

tera- T 1012

peta- P 1015

yotta- Y 1024

Other units

• Light year – 9.4605284 × 1015 m

• Parsec – 3.26 light years

A voyage to very large and very small

• http://htwins.net/scale2/

Compressing the “very large” into a meaningful scale

• The Eau Claire Planet Walk– 1.1 miles = distance from Sun to Pluto, scale = 3.4 billion:1

• The Cosmic Calendar– 1 year = time since the Big Bang (13.7 billion years)– http://www.youtube.com/watch?v=Ln8UwPd1z20