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# 900 Pre - Lab 7 ID#` Section_ Pre- lab : Structure and Motion of Spiral Galaxies Hand in this pre- lab at the beginning of the Spiral Galaxies lab .

can you please answer these for me thank you, I do not understand it one bit

900
Pre - Lab 7
ID#`
Section_
Pre- lab : Structure and Motion of Spiral Galaxies
Hand in this pre- lab at the beginning of the Spiral Galaxies lab .
1) The disk of the Milky Way is about 100, 000 light years in diameter and 1 , 000 light
years thick . What is the ratio of diameter to thickness of the Milky Way ?\
2 ) Name an everyday object that has the same diameter - to - thickness ratio as the Milky*
Way , and demon
Ate that it does `
sing estimates of the size / thickness ; this should be
. with a severe
ly similar shape to the Milky Way . Draw ( a) this object , and
( b ) the Milky Way , edge- on and face - on .\
The Sun actually moves relative to nearby stars and relative to the center of the Galaxy .
The speed of the Sun and other stars is one of the most important ways astronomers can
learn about the structure of the Milky Way .\
3 ) First , write the equation relating time , distance , and speed .&quot;
The Sun moves up and down in the disk of the Milky Way , covering a distance of about
2 , 000 light years ( 1. 9* 10 Kilometers ) in 65 million years ( 2 . 1 x 10 seconds ) .
4 ) What is the Sun's average speed in this motion ( in km / s ) ?&quot;
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5) The time required for an object to complete one orbit is called the period, P. For an
object in circular motion, what is the distance traveled in time P if the radius of the
object's orbit is a distance R? Draw a picture, and indicate the path travelled in the
orbit.
6) Using the relationships you wrote above, write a formula for the speed, v, of an
nigh
object in a circular orbit, in terms of P and R.
ure
In 1
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The Sun is about 28,000 light years, or 2.65 x 10 7 km, from the center of the Galaxy, and
orbits in a circle with a period of 230 million years, or 7.25 x 10&quot; seconds.
7) What is the speed of the Sun's orbit in kilometers per second?
anr
8) The Sun and other nearby stars orbit the center of the galaxy in a motion like a
carousel horse, bobbing up and down as they orbit around the center of the Galaxy.
(a) Based on the two velocities you calculated above, which is the dominant motion?
(b)So is this merry-go- round ride &quot;smooth&quot; or &quot;bumpy&quot;?

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