Lect09

# Lect09 - PHYS 172 Modern Mechanics Fall 2009 Lecture 9...

This preview shows pages 1–7. Sign up to view the full content.

Fall 2009 PHYS 172: Modern Mechanics Lecture 9 – Buoyancy, The Energy Principle Read 5.1 – 5.7

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
CLICKER QUESTION #1 Reading Question (Sections 5.1 – 5.7) (This is a closed-book quiz, no consulting with neighbors, etc.) A. The force of Earth’s gravity causes work to be done on the Moon, giving it energy of motion. B. No work is done on the Moon because the net force on it is zero. C. The work done on the Moon causes it to be in a circular orbit. D. No work is done on the Moon. E. The Earth’s gravity gives the Moon kinetic energy. The Moon is in circular orbit about the Earth. Which statement is most correct ?
Today’s Lecture • Buoyancy,Rest Energy, Kinetic Energy, Work

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Just a few words about: Pressure Balloon: Air molecules constantly hit surface and bounce off, exerting forces on surface. on small piece of surface of small piece of surface pressure area F P ! " Colliding ball exerts force on wall. on due to on due to on due to ball wall ball wall wall ball ball p F t F F ! = ! = " r r r r v r
Just a few words about: Buoyancy There are more air molecules here than here Air is denser closer to the earth. (Why? We’ll see in Chapter 12!) Thus P bottom > P top OR Net force pushing up > Net force pushing down buoyancy

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
6 Buoyancy: macroscopic view air m g r buoyant F r Archimedes principle: any body partially or completely submerged in a fluid or gas is buoyed up by a force equal to the
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern