Physics 272: Honors Physics II
Spring 2017

# Wednesday 25 January 2016: Topics to be covered in the lecture (recap HRW section 14.5, new sections 14.6-7)

• Finish discussion of Archimedes' principle
• Fluid flow: current density and continuity
• Bernoulli's equation

1. At the end of Monday's lecture, we did an iclicker question on ducks floating in water that most students got wrong. Here is a second chance on a similar question! Note that the main reason for getting the clicker question wrong was the implicit (wrong) assumption that the amount of water in each beaker is the same -- but think about it: the levels are the same, so the amount of water has to be different in the three cases. Now do question #1 in the quizlet.

2. Introduction to the concept of "flow rate." Imagine a museum with one entrance and one exit. People enter the museum at the rate of 127 per hour (that's about 2 per minute). This is the "number flow rate" into the museum. Now do question #2 in the quizlet.

3. More on the "number flow rate." If there is more than one exit, you have to add the number flow rates to get the total rate at which people exit the museum. Now do question #3 in the quizlet.

YOU SHOULD PREVIEW THE QUIZ QUESTIONS HERE TO BE READY TO ENTER THEM WHEN YOU START THE QUIZ IN QUIZSTAR.