slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Announcements PowerPoint Presentation
Download Presentation
Announcements

Loading in 2 Seconds...

play fullscreen
1 / 20

Announcements - PowerPoint PPT Presentation


  • 66 Views
  • Uploaded on

Announcements. CAPA Set #7 due Friday at 10 pm This week in Section  Assignment 4: Circular Motion & Gravity Finish reading all sections of Chapter 5, start Chapter 6 in Friday’s lecture this week Reminder  Exam #2 on Tuesday, October 11

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Announcements' - marcin


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Announcements

  • CAPA Set #7 due Friday at 10 pm
  • This week in Section 
  • Assignment 4: Circular Motion & Gravity
  • Finish reading all sections of Chapter 5, start Chapter 6 in
  • Friday’s lecture this week
  • Reminder  Exam #2 on Tuesday, October 11
  • See course web link (“exam info”) for details
  • Reminder about office hours …
  • Nagle (Monday 2-3 in office, Wednesday 1:45-3:45 pm help room)
  • Kinney (Thursday 4-5 pm help room)
  • Uzdensky (Tuesday 11am-noon help room)
l ab m ake up p rocedure
Lab Make-Up Procedure
  • You must complete at least 5 of the 6 labs to receive a passing grade in this course.
  • If you missed a lab, you can make it up during one of two Review/Lab make-up weeks:
    • October 24-28 (labs 1-3)
    • December 5-9 (labs 4-6)
  • Even if you don’t need to make up a lab, you still mustattend your section those weeks for the Review Recitation.
  • To make up a lab, contact your TA ahead of time.

You will need to arrange attending twice: (1) for lab make-up

and (2) for the review recitation. You can attend any other section (in addition to your regular section), if you have that section’s TA permission in advance.

Contact: Professor Uzdensky if there are any questions.

slide3

Earth at the Center of Everything

Geocentrism

- Epicyles

- Equant

- Deferent

Claudius Ptolemaeus

(Ptolemy)

90 – 168 AD

slide4

Heliocentrism (Sun at the Center)

Nicolaus Copernicus

1473-1543

Johannes Kepler

1571-1630

Tycho Brahe

1546-1601

De revolutionibusorbiumcoelestium

(On the Revolutions of the Celestial Spheres)

Heliocentrism

Three Laws

astronomical observations

Epitome astronomia Copernicanae

(Epitome of Copernican Astronomy)

slide5

Kepler’s Laws of Planetary Motion

Law #1: The orbit of each planet is an ellipse,

with the Sun at one focus.

slide6

Elliptical Geometry

The sum of the distances from any point P on the ellipse to those two foci is constant and equal to the major diameter ( PF1 + PF2 = 2a ).

slide7

Kepler’s Laws of Planetary Motion

Law#2: An imaginary line drawn from each planet to the Sun sweeps out equal areas in equal times.

slide8

Room Frequency BA

Clicker Question

Notice how a planet with an elliptical orbit moves closer to and further away from the Sun. The point of closest approach to the Sun is called perihelion. The furthest point is called aphelion.

At which position is the asteroid moving

at the largest magnitude velocity?

Far left (aphelion)

Far right (perihelion)

Top

Bottom

Same velocity magnitude everywhere

slide9

Kepler’s Laws of Planetary Motion

Law #3: The ratio of the square of a planet’s orbital period is proportional to the cube of its mean distance from the Sun.

slide10

What is the relationship betweenvelocity and orbit Radius?

Consider F=ma in the radial direction: +inward

Force of Gravity Only

Rs

Condition for Circular Motion

Re

h

elevation

Rs = Re + h

slide11

Room Frequency BA

Clicker Question

Satellite 1 is in circular orbit about the Earth and is moving with tangential speed v1.

Satellite 2 is also in orbit but with speed v2 > v1.

Satellite 2’s orbit radius is:

Bigger than Satellite 1’s

Smaller than Satellite 1’s

Unclear from the information given.

Rs

Re

h

elevation

Rs = Re + h

slide12

Room Frequency BA

Clicker Question

Satellite 1 is in circular orbit about the Earth with radius R1.

Satellite 2 is also in circular orbit with a radius R2 and a speed twice that of Satellite 1.

What is true about the radii?

R1 = 2 x R2

R1 = ½ x R2

R1 = 4 x R2

R1 = ¼ x R2

Unclear from the information given.

Rs

Re

h

elevation

Rs = Re + h

slide13

Room Frequency BA

Clicker Question

Eliminate velocity in place of period (T)

Period T

Rs

Which of the following correctly presents the relationship between Rsand T?

Re

h

elevation

Rs = Re + h

slide15

Knowledge of a planet’s period (easy to measure)

allows us

to determine it orbital radius.

Where is Mars?

Mars is 1.52 times as far away as the earth is from the sun.

slide16

Exoplanets

Upsilon Andromedae is a binary star located about 44 light-years away from the Earth. The primary star is a yellow-white dwarf star that is younger than the Sun. There is a second star that is a red dwarf in a wide orbit.

As of 2010, four confirmed extrasolar planets have been discovered.

(b)  (0.0595)3/(4.61)2=9.9x10-6 AU3/days2

(c)  (0.832)3/(241.3)2=9.9x10-6 AU3/days2

(d)  (2.53)3/(1278.1)2=9.9x10-6 AU3/days2

(e)  (5.24)3/(3848.8)2=9.7x10-6 AU3/days2

slide20

Discovery of accelerating universe!

Need a large scale repulsion force (not gravity).

No one knows what it is – just called Dark Energy!