Polar coordinate problems

  • #1
HELP!!!! I just got this assignment over the email a couple hours ago and it's due in the morning and I have no clue how to do these problems! I've spent a few hours trying to figure this stuff out on my own, but I'm down to these last few and I just can't do it. if you can answer one or more, I really appreciate anything AT ALL. I'm sorry I don't have much done already, but I've got a brain block and I'm starting to panic. please help!!!


2. If a satellite circles the earth at 9000 km from the center, estimate its period T in seconds.

3. Convert 1/r = C - Dcos(theta) or 1= Cr-Dx into the xy equation of an ellipse.

5. The Earth takes 365.25 days to go around the sun at at distance d = 93 million miles = 150 million km. find the mass of the sun.
F=ma=constant/r^2.
 
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  • #2
tiny-tim
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2. If a satellite circles the earth at 9000 km from the center, estimate its period T in seconds.

Hi imsoconfused! :smile:

2. Either compare t with the period of the moon (erm … that's one month! :wink:) …*that only works if you know how far away the moon is, of course.

Or work out the gravitational force on it, by comparing it with g at the earth's surface … that only works if you know the radius of the earth … and then use centripetal acceleration :smile:
 
  • #3
HallsofIvy
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HELP!!!! I just got this assignment over the email a couple hours ago and it's due in the morning and I have no clue how to do these problems! I've spent a few hours trying to figure this stuff out on my own, but I'm down to these last few and I just can't do it. if you can answer one or more, I really appreciate anything AT ALL. I'm sorry I don't have much done already, but I've got a brain block and I'm starting to panic. please help!!!


2. If a satellite circles the earth at 9000 km from the center, estimate its period T in seconds.

3. Convert 1/r = C - Dcos(theta) or 1= Cr-Dx into the xy equation of an ellipse.
Multiply through by r first. r= [itex]\sqrt{x^2+ y^2} and r cos(theta)= x. You may need to square both sides of an equation to get rid of the square root and get the (standard)equation of an ellipse.

5. The Earth takes 365.25 days to go around the sun at at distance d = 93 million miles = 150 million km. find the mass of the sun.
F=ma=constant/r^2.

Problems 2 and 5 are not mathematics problems. They are physics problems and I would be surprised if your book does not have formulas that apply directly.
 

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