Sep. 18 In-class Optional Assignment

You can earn credit on this assignment if you weren't in class on Friday by answering the following questions and then turning in your answers at the beginning of class on Mon., Sep. 21.

1.    Archimedes Law tells us that a 1 gallon bottle is immersed in water (in a swimming pool for example) will         experience an 8 pound upward bouyant force (because a 1 gallon bottle will displace 1 gallon of water and 1 gallon of water weighs 8 pounds).  Archimedes Law allows you to determine the strength of the upward buoyant force but doesn't tell you what causes it.  What does cause the upward bouyant force?

2.   Kilograms or grams are units of mass in the metric system.  In the metric system, weight has units of dynes or Newtons. 
2a.   What units are used for weight in the United States?
2b.   What units are used for mass in the United States?

3a.   Does air pressure  INCREASE  DECREASE  or remain  CONSTANT  with increasing altitude?
3b.   Does air density  INCREASE  DECREASE  or remain  CONSTANT  with increasing altitude?

4.   Air in the troposphere can be stable or unstable.  The stratosphere is always a very stable layer.  What is the difference between a stable atmosphere and an unstable atmosphere?  I.e. what can happen in an unstable atmosphere that doesn't happen in stable air?

5.   How many feet are in 1 mile?