To calculate the mass of the milky way wouldn't we need to know the mass and velocity of something orbiting the milky way or something the milky way is orbiting? As i understand it you set GMm/r^2=mv^2/r where M is the mass of the milky way and m is the mass of something orbiting the milky way
The milky way is the galaxy that contains our solar system. It contains hundreds of billions of stars and planets. It's over 100,000 light years long. Our solar system does orbit the center of the milky way, it's a cosmic year.
I know I'm a little late but for those still having trouble, I found, to determine the mass of the milky way is; M=(Distance of the sun to the center of the galaxy)^3/(The time taken for the sun to orbit the center of the milky way)^2 }Use of kepler's third law
You are missing an m in FG. The force is between two objects m1&m2. Your equation only has one. Then it become a matter of finding the information. Arsene posted a link with the data necessary for the rest othe problem.
I've been trying to study for this quest and I have even found a helpful videos http://www.youtube.com/watch?v=xXxtgoPcKC0 http://www.youtube.com/watch?v=weRijaStAXA but for some reason I still do not feel ready for it.
I am confused how els to study for the quest does anyone know of any practice problems we could do.... and also is the G always going to be 6.67 x 10 ^11 ?
Hey Haley, I found some practice problems with the answers. Sort of helpful. http://highered.mcgraw-hill.com/sites/0072509775/student_view0/chapter5/practice_problems.html
How does one go about calculating the mass of the milky way. what equation should i use?
ReplyDeleteThis is for AP, correct?
ReplyDeleteWhat's the accepted mass of the Milky Way? Is this even for our class? -Jessie Higbee
ReplyDeletefor the mass of the sun if i use Fc=mv^2/r and fc=mg, doesn't mass cancel?
ReplyDeletehttp://imagine.gsfc.nasa.gov/YBA/cyg-X1-mass/mass-of-sun.html danielle, for mass of the sun, maybe this helps?
ReplyDeleteIs this for our class?
ReplyDeletewhat would the two reference objects be to calculate the mass of the milky way?
ReplyDeletealso, what would be the radius to calculate the mass of the milky way?
ReplyDeleteI have the same question as Jade about the mass canceling out if Fc=mg. -Jess Higbee
ReplyDeleteYes the mass doe cancel out but that's the mass of the earth on both sides not the sun.
ReplyDeleteBesides calculating the mass for the sun and Milky Way, was there any other work that we are suppose to do for the day Crane was out?
ReplyDeleteTo calculate the mass of the milky way wouldn't we need to know the mass and velocity of something orbiting the milky way or something the milky way is orbiting? As i understand it you set GMm/r^2=mv^2/r where M is the mass of the milky way and m is the mass of something orbiting the milky way
ReplyDeletei think maybe the mass of the object orbiting cancels out because for that object Fg=Mg=GMm/r^2 (Ms cancel) but I could be wrong?
DeleteDraw a picture Fc is the force acting on the thing going in a circle. Does the earth go around the sun or does the sun go around the earth?
DeleteI believe the "m's" will cancel out. Right?
ReplyDeleteYes, one of the M's on each side will cancel out, leaving GMmw/r=v^2 as one R will cancel as well
DeleteThis should help
ReplyDeletehttp://crab.rutgers.edu/~gambs/astronomy/Review2002.doc
Wait does anything orbit the Milky Way? Or does the Milky Way orbit anything?
ReplyDeleteMary Frances Wenig
The milky way is the galaxy that contains our solar system. It contains hundreds of billions of stars and planets. It's over 100,000 light years long. Our solar system does orbit the center of the milky way, it's a cosmic year.
DeleteI know I'm a little late but for those still having trouble, I found, to determine the mass of the milky way is;
ReplyDeleteM=(Distance of the sun to the center of the galaxy)^3/(The time taken for the sun to orbit the center of the milky way)^2
}Use of kepler's third law
I am confused on how to do these. I tried setting mv^2/r=m=Gm/r^2 but I dont know where to go from that,
ReplyDeleteYou are missing an m in FG. The force is between two objects m1&m2. Your equation only has one. Then it become a matter of finding the information. Arsene posted a link with the data necessary for the rest othe problem.
DeleteIs the Quest only on the force of gravity and centripetal force?
ReplyDeleteI feel like I should know this, but what is the difference between G and g?
ReplyDeleteG is also a universal constant
DeleteG works anywhere in the universe at any distance between any two masses.
ReplyDeleteg works on earth, is at the surface of the earth and has a value of 9.8
Mr. Crane, what is on this quest besides centripetal force and gravity and mass calculations?
ReplyDeleteSo does anybody need any help with anything?
ReplyDelete-Dave
Besides G being constant, will we be given certain values to solve problems or will we have to calculate things such as the period or radius?
ReplyDeleteHe has to give us values because we have no way of say calculating or memorizing the mass of the universe without him telling us
DeleteI've been trying to study for this quest and I have even found a helpful videos
ReplyDeletehttp://www.youtube.com/watch?v=xXxtgoPcKC0
http://www.youtube.com/watch?v=weRijaStAXA
but for some reason I still do not feel ready for it.
I am confused how els to study for the quest does anyone know of any practice problems we could do.... and also is the G always going to be 6.67 x 10 ^11 ?
ReplyDeleteHey Haley, I found some practice problems with the answers. Sort of helpful.
Deletehttp://highered.mcgraw-hill.com/sites/0072509775/student_view0/chapter5/practice_problems.html
These were really helpful. Thanks.
Deletethat will always be G because G is a constant so it never changes
DeleteG is actually 6.67 x 10 ^-11.
DeleteI also was wondering for the milky way problem was the units Pc were for and AU?
ReplyDeleteAU stand for astronomical units which is the distance between the earth and the sun, but we didn't use them to solve the problem
DeleteAre we going to have anything like the milky way problem on the quest thing? I feel like that's the only thing I'm not really confident about.
ReplyDeleteIs there anything other than the equations that we should have memorized? Like constants or anything like that?
ReplyDeleteMary Frances Wenig
If something is accelerating can F=F?
ReplyDeleteMary Frances Wenig
No, the forces can't be equal if the object is accelerating.
Delete