Homeworks 1: Difference between revisions

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'''Homeworks 1''' is the attempted solution to our second task<ref>Our first task was to register our PRS, visit the course web-page on Blackboard, look at the textbook, and write an equation for our wiki</ref> in the course [[AST4210_5211: Introduction to Astrophysics - Fall 2009|Introduction to Astrophysics]]. This assignment is due on ''Wednesday 09/09/09'' and was assigned on 09/01/09.
'''Homeworks 1''' is the attempted solution to our second task<ref>Our first task was to register our PRS, visit the course web-page on Blackboard, look at the textbook, and write an equation for our wiki</ref> in the course [[AST4210_5211: Introduction to Astrophysics - Fall 2009|Introduction to Astrophysics]]. This assignment is due on ''Wednesday 09/09/09'' and was assigned on 09/01/09.


==Problem 1==
List in order of increasing size and give the approximate size of the following objects: An atom,
a biological cell, a cluster of galaxies, the Earth, a galaxy, the Local Group of galaxies, a neutron, a neutron star, a person, the Solar System, our sun. Note: you may have to look in other books besides your textbook to get all this information.


==Problem 2==
The nearest star outside the solar system is about 4 light years away.
* How far away is the star in kilometers?
* Suppose you travel to the nearest star in a rocket ship moving at 100 km per hour (100 km/hr is
about 62 mi/hr, a typical automobile speed on a Florida highway). How many years will it take
you to get to the star?
* Suppose you travel to the star at 10 km per second (the speed of a rocket in orbit around the
Earth). How many years will it take you to get to the star?
==Problem 3==
Use the size of the Astronomical Unit in kilometers and the length of the year in seconds to calculate how fast the Earth moves in its orbit in kilometers/second.
==Problem 4==
Describe the essential differences between the Ptolemaic, Copernican, and Keplerian descriptions
of planetary motion.
==Problem 5==
Use Newton’s laws to show that the orbits of planets are ellipses.


==References==
==References==
<references/>
<references/>

Revision as of 19:38, 6 September 2009

Homeworks 1 is the attempted solution to our second task[1] in the course Introduction to Astrophysics. This assignment is due on Wednesday 09/09/09 and was assigned on 09/01/09.

Problem 1

List in order of increasing size and give the approximate size of the following objects: An atom, a biological cell, a cluster of galaxies, the Earth, a galaxy, the Local Group of galaxies, a neutron, a neutron star, a person, the Solar System, our sun. Note: you may have to look in other books besides your textbook to get all this information.

Problem 2

The nearest star outside the solar system is about 4 light years away.

  • How far away is the star in kilometers?
  • Suppose you travel to the nearest star in a rocket ship moving at 100 km per hour (100 km/hr is

about 62 mi/hr, a typical automobile speed on a Florida highway). How many years will it take you to get to the star?

  • Suppose you travel to the star at 10 km per second (the speed of a rocket in orbit around the

Earth). How many years will it take you to get to the star?

Problem 3

Use the size of the Astronomical Unit in kilometers and the length of the year in seconds to calculate how fast the Earth moves in its orbit in kilometers/second.

Problem 4

Describe the essential differences between the Ptolemaic, Copernican, and Keplerian descriptions of planetary motion.

Problem 5

Use Newton’s laws to show that the orbits of planets are ellipses.

References

  1. Our first task was to register our PRS, visit the course web-page on Blackboard, look at the textbook, and write an equation for our wiki