PHYS 130 Lecture 2 Homework

Yes, you have homework.  It is simple.  Comment on this post.  That is all.

Why?  Well, I think the best way to communicate is online – and why not through this blog.  You will need to comment in the future anyway since I will want you to link to anything that you make.

What should you say in your comment?  Here are some suggestions:

  • “hello”
  • you could ask a question about the class or something
  • you could share a link to something cool
  • how about a poem?
Advertisements

106 Responses to PHYS 130 Lecture 2 Homework

  1. caleb says:

    Hello. I was reading this while drinking coffee this morning.

    http://physics.aps.org/articles/v4/65

  2. Robin Joshi says:

    Hello . How is this homework ? 🙂

  3. irioth says:

    Whatsup guys. Astronomy is probably what originally got me into Phsics and I was pretty active on the Space.com forums (there are occasionally physics discussions there) at one point. I still enjoy Astronomy and occasionally keep track of space-related news on the site. This article looks interesting.

    http://www.space.com/12731-diamond-alien-planet-discovered-neutron-star.html

    Oh! And I did my senior year of high school in an online homeschool program and I took a physics course. Naturally I had to do all my labs online and we borrowed most programs from the University of Colorado at Boulder. Their simulations for basic (and some not so basic) physics principles are all completely free! Check it out:

    http://phet.colorado.edu/en/simulations/category/physics

    They also have sims for Biology, Chemistry, etc which can be pretty cool if you enjoy those subjects.

  4. Sean says:

    Hey! I posted already so you might get it twice, but for some reason it logged me into my wordpress account when I posted the first time and I doubt anyone here would know me by “Irioth.” Anyways, I have two interesting links for you guys to check out. The first is an article on space.com (a great place to keep up with space-related news if you are interested in that sort of thing like me) and the second is a site where you can download all kinds of really interesting physics (and other science) related lab simulations. I know about this site because I took Physics in my senior year of high school (online/homeschool) and we used them for our labs.

    http://www.space.com/12731-diamond-alien-planet-discovered-neutron-star.html

    http://phet.colorado.edu/en/simulations/category/physics

  5. Hey guys, I guess I should share my resources as well.
    Physorg.com and Sciencedaily.com
    Enjoy.

  6. Mason says:

    Tough homework assignment…

  7. Crews Culler says:

    I love physics! ha

  8. Kayla Hoover says:

    Well, I love this Physics class already. This homework assignment took me a total of five seconds. I think you should talk to the rest of my instructors regarding their assignments…just saying.

  9. Nicole says:

    hello! i thought this was a pretty funny article!

    http://organizations.oneonta.edu/physicsclub/catphysics.html

  10. Tuan Tran says:

    Sup will we be talking about the possibility of time travel? ITS SCIENCE

    • rhettallain says:

      You are time traveling right now. You are going into the future at a rate of 1 second per second. SCIENCE!!!!!

      • iriothSean says:

        Didn’t know how to get ahold of you Dr Allain, but my blog is up. Not much too it, but its there.

        http://donttimetravel.wordpress.com/

        What is your SE email?

      • Sumit Rawat says:

        I had learnt from discovery channel that if we can make our-self travel nearly at the speed of light then, we can time travel, but in forward direction only… That’s practically impossible, however. Is there any theory that explains time travelling into the past? That would be fun!!!

      • rhettallain says:

        There are several ideas about traveling backwards in time. I could give you some hints, but it might be more fun for you to research this idea and write it up as a blog post.

  11. Keaton Carter says:

    funniest.video.ever.

  12. Rajendra Paudel says:

    I cannot even imagine of majoring in any other subjects other then physics.. I love physics..

  13. Heather Blees says:

    Hello… sorry it’s not more creative much writing to be done for english

  14. Elliot Crosby says:

    Hi there.

  15. Hey guys, There is a great youtube channel dubbed Sixty Symbols that is based out of the UK. Lots of interesting material, Check it out. http://www.youtube.com/user/sixtysymbols

  16. Ramesh Shrestha says:

    Some great lectures from stanford university
    ..
    http://www.youtube.com/user/StanfordUniversity

  17. Pratik says:

    this might not be related to the topic. O, there’s no topic!! i m trying to solve Rubik’s cube. i can do a single face.. however, i want to complete all the six faces. Can anyone suggest the way to do it . or send me a link from somewhere. please do not send me link from you tube.. they are useless..

  18. ethanmartin93 says:

    helloooooooooooooooooooooooooooooooooooooooooo!

  19. Hello, my name is Seth and I’m a Physics Major. Obvious? It happens.

  20. Keyanna Buckner says:

    Well im posting a “comment”
    I’m eatinf chicken.

  21. Sarju Adhikari says:

    hey…whats up!!!!! my name is sarzu and I’m a Chemistry major. But, it’s obvious that i love Physics……

  22. Hunter M. says:

    Hello there!! You know, I’ve been thinking about my major choice. I love physics and I plan on going with Chemical Engineering as well. But, I’ve heard of astrophysics.. can anyone give me a good resource to find out more about it?? Thanks!! 🙂

    • rhettallain says:

      Essentially, astrophysics takes physics principles and applies them stuff in space – like stars and black holes and things.

      If you are interested in astrophysics, there typically is not an undergrad degree in this. You would be a physics major and then focus on astrophysics in graduate school. If I find a resource, I will post it.

    • Anish Karki says:

      hey buddy,,,I love chemical engineer tooo..can any one tell me the pre-requisite of chemical engineering ??

  23. Darpan Shrestha says:

    Hi…..I love physics but I am interested in Civil Engineering also… Can I complete my undergraduate in Physics and graduate in Engineering?

    • rhettallain says:

      Yes. You can easily get a BS in physics and go to graduate school in engineering. It is more difficult to go the other way (BS in engineering and graduate school in physics) but that can be done if you take enough physics courses.

      Don’t forget that we have the 3-2 physics/engineering program. Spend 3 years at Southeaster and 2 at LSU and get both BS in physics and a BS in engineering. Win-win.

  24. Sumit Rawat says:

    I got a bunch of questions here.

    1. We say positive charge and negative charge…. But what is a charge to be exact?
    2. What is an electron made up of or what is the smallest existing particle made up of?
    3. What is left if we take out space from space?
    4. A black hole engulfs everything that comes in its way. This means it’s volume ( I guess it must have a certain vulome, although relatively very small) gets larger and larger and hence its gravitational pull also gets intensified.. So, is it possible that it will engulf the whole universe at some point of time? (( Dont laugh if you think it is a stupid question)
    5. They say the whole universe thing started out with a big bang. Where was the universe before?
    6. Doppler’s Red shift or something like that bla bla bla says that the universe is expanding.. what is the platform where our universe is expanding?

  25. Sagun G.C says:

    which is more important to physicist , a wild yet controlled imagination or strong mathematical knowledge?

    • Sumit Rawat says:

      Sagun, Einstein said, Imagination is more powerful than knowledge. I guess, imagination is the foundation to a strong mathematical base….

  26. santosh says:

    hi everyone..watch this if you have some spare time…
    Revelation of the Pyramids
    http://www.sockshare.com/file/FDF803EC13C709FB

  27. austin sunde says:

    hello

  28. gregory sunde says:

    cool class

  29. Casey Guitreau says:

    I love Rhett Allain’s physics class!!!

  30. Apsana Shrestha says:

    I am trying that sphagetti demonstration in my kitchen soon. I loved that video.

  31. Sagar Pokhrel says:

    Hey, guys just go through the embedded youtube link. The video talks about the concept of gravity train…..

  32. azphysics says:

    want to know about black holes?? then watch this

  33. Gregory says:

    Hello…..good to go!!

  34. Ray Butler says:

    Hello. Interesting homework, I spent my time looking at what everyone else post.

  35. Robert says:

    so i guess here is my homework. peace

  36. Anish Karki says:

    Hey what’s up ?? Who said that Physics is difficult…it’s interesting :p

  37. mcj03 says:

    Hi. I wish my homework in my other classes were as easy as this.

  38. Apsana Shrestha says:

    I loved that sphagetti demonstation…I am going to try in my kitchen soon!

  39. Dilip Kharel says:

    Hey everyone. This is the coolest Physics class I’ve ever attended!!

  40. hi everyone …seems there is some interesting coments going on.. Ah, I had seen one coment talking about time travel. Well, I have spent a lot of my time reading about Stephen’s hawking “a brief history of time”, I would like to share something. Yes, time travel is possible. As einstein says time slows down in high speed and time changes with gravity.The satellite we use for gps which orbits the earth has different time than that on earth. This difference is very very small but it can’t be denied that it will not make a difference in gps mapping. I want to share something about time travel. lets say (hypothetically) if one goes in a spaceship and revolves around a black hole (which has infinite gravity) for certain period that time will be will be slowed down. Meaning lets say he begins travelling in 2010 and returns to earth in 2012 but when he returns to earth time year will be far ahead may be 2020 or more. This means we have travelled forward in time..Its like travelling forward in time. But, I have something to share about travelling back in time. If we travel back in time, there will be a condition of paradox. Let’s take an example. lets say one is holding a gun for about 5 mins, then lets say after five mins, he travel back 2-3 mins and he shoots him. What happens then?? Stephen hawkings describe this as a paradox which cannot happen. There is a theory that time travel can also be done through warm hole. If someone is interested about cosmology and time travel, I would suggest reading articles or watch videos from Michio Kaku and Stephen hawkings. I have created a blog but haven’t got time to post materials there yet but I will be active soon there. I would like to invite you to my blog which is http://kakolukia786.blogspot.com/

    Thanks

  41. I will soon be active in my own blog where I will try to post cool stuff about space, time and the so called hot topic string theory.. Thanks. If anyone is interested watching free online lectures from MIT, you can visit ocw.mit.edu… thanks

  42. One last comment..one can google time dilation which describe time changes and is not constant. I guess concept of time travel also comes from this one. I guess Einstein was the one who added a new dimension that is time and said that space and time are not different but can be viewed as one which he described it as space-time.

    • You may already be familiar with the concepts, but it may be worth your while to read the book “Simply Einstein”. I read this book my sophomore year of high school and it was my first introduction to relativity and its implications. It is nontechnical with some equations yet lucid.

  43. Sean says:

    Oh yeah, the paradox. More common form is the Grandfather paradox in which go into the past and kill your grandfather before he gets a chance to concieve your father. In this case you cease to exist because your father never came into existence, but that also means that you never could have killed your grandfather in the first place because you never existed. So, since you did not exist, and therefore could not have killed your grandfather, he must have given birth to your father who gave birth to you, meaning you exist. If we take out all the in between there, we get the statement:
    Because you do not exist, you do exist. Wierd. And thats the Grandfather Paradox.

    I mentioned another reason why time travel into the past might theoretically be a bad idea on my blog donttimetravel.wordpress.com.

    As for time traveling into the future (we can call it that), you are certainly correct. The example I always recieved was that of the black hole’s event horizon and the astronaut hanging from a rope just barely outside the event horizon, with the rope tied to his ship “flying” away from the black hole with enough force to keep it suspended in the exact same spot. Time for the astronaut would theoretically come almost to a complete stop (though not quite) while time for the ship would be extremely slow, and time for earth would pass normally. You can imagine a century passing here on Earth and meanwhile only a few seconds had gone by for the astronaut and only a few years for his ship (though I do not know the exact ratio).

    Its interesting to imagine what it would be like for the people on the ship watching their comrade hanging from the rope. They would perhaps percieve his movements become so slow that they would virtually halt. They could moniter his movement over the course of days, months, or perhaps years. But then you can visualize that he would be watching them move obscenely quick, perhaps to such a degree that they would be dead within minutes (his minutes) of him reaching the brink of the event horizon. Of course, this is all assuming that the light going to and from the astronaut and his crew is not subject to the distortion of time (which is not realistic, but is useful for visualization purposes).

    Honestly, I think Black Hole Preservation is the Cryogenics of the future. So you’re dying of an incurable disease and we won’t have the cure for another 300 years. “Just give us, BHCryoSpace all of your worldly possessions and we will fly you out to the brink of the nearest black hole and keep you suspended there for the next 300 years (though it will only feel like a couple of days for you)! Then, at the end of your stasis period when the cure is available, we will come back out and fly you back to Earth where you can recieve your treatment. *small print* warning: may cause death, skewed perception, dizziness, bloating, heaviness in the legs/torso/arms/chest/face/eyes/ears/and other bodily sections, a feeling of weighing much more than seems possible, loss of family, loss of friends, loss of civilizations, homesickness, generalized depression/compression, sore hands, chafed fingers – not a recommended treatment plan if you have suicidal thoughts; please consult your physician before agreeing to the Black Hole Preservation Treatment.” Yeeaaahhh… that’s definately going to happen. Would be awesome though to go camp out there for a day or two and come back 1000 years in the future. I’d volunteer.

  44. JamesPatterson says:

    just something cool with helicopters

    and hi Dr Allain

  45. Blake Randol says:

    Hey. How’s everybody doing?

  46. Brayden Stephens says:

    I just realized how unreliable the internet access on campus is due to the fact that I tried to post a comment 2 weeks ago from my iPhone and just realized it never went through.. Thanks AT&T….

  47. Hello all. Better late then never. 😀

  48. robin joshi says:

    hey all just wanted to post this amazing video. What kind of force would it take for a car to go up in the air like that ? Are the forces tangential to the tires? I’m having trouble embedding the video into this post . here’s the link again in case you missed it : http://www.youtube.com/watch?v=L5N7R9Wbe_E

  49. Ray Butler says:

    I know this is a ridiculous time of the night to send this, but i realized i hadn’t posted my url address. It’s http://randomphys130.dinstudio.com/

    Both blogs are there.

  50. Dilip Kharel says:

    Hey everyone, this is my first blog.

    http://tutormephysics.blogspot.com/

  51. physgeeks says:



    this is my blog post. the idea is awesome. read it.

    Who doesn’t want to travel at high speed and reach long distances in just a few minutes, spending couple of bucks? The world is gaining speed and people want to move quickly. They want to travel long distance in less time and money. The answer to this question is gravity train. Gravity train uses gravity of the earth to gain the speed and to stop at the station as well. So no external energy at all.
    The concept of gravity train is awesome. According to the physicists, the time that takes to travel across the world is about 42 minutes and some seconds. Anywhere you travel it takes only 42 minutes. So if you are in Paris and want to travel to New York for lunch, it is no longer a dream. All around the world in 42 minutes.
    The idea behind the gravity train is to use gravity to construct a tunnel right through the earth centre and use it to travel another place. In this process, the train uses the gravity on one surface of the earth to gain the speed and use the gravity on the other side of the earth to stop the train. So no external energy used at all. This train even saves millions of dollar that is spent on fossil fuels and other type of energy. This saves both money , energy and time. But there are some problems to convert this dream into reality.
    First of all the train, in order to gain such high speed there should air friction in the tunnel. So the air in the tunnel should be pumped out and made vacuum in order to get the high speed that is necessary . the other problem is the incredibly high temperature and pressure at the centre of the earth. So it is necessary to find the solution to these problems to turn the dream of travelling the world in just 42 minutes .
    The first problem can be solved easily but the second problem is kind of hard to solve. Now physicist are working to solve the problem of high pressure and temperature and the centre of the earth. They are saying that the time that is need to travel from one end to another end of the world is constant even if you constructed the tunnel at certain angle from the centre of the earth. But it is very hard to dig very deep into the earth . So the idea of gravity train is fascinating but it is little hard to do it. There is still some possibility that the future technology can solve this problem and make this dream a reality.

  52. By Sagar Shahi

    As known to many people in the world, magnet generally has two poles, North Pole and South Pole. Magnetic lines of forces are created by the North Pole and reaches the South pole. Magnetic Poles always exists together at all level. If you break down a ordinary bar magnet into pieces, you will again get a smaller magnet with North Pole and South Pole. So, we can infer that a magnet always has magnetic North Pole and South pole, but there are some physicist who argue that there are some magnets with either of the poles . According to them magnetic monopole like electric monopoles, is possible.
    Magnetic monopole is a magnet with only one pole, i.e. either the magnet has North Pole or the South Pole just like electric charges, electrons and protons. But for now magnetic monopole can be defined as a hypothetical particle that is with only one pole ( a north pole without a south pole and vice-versa). It can also be referred as “net magnetic charge”. There are many scientist in the world who believes in the concept of magnetic monopole. Based on the existence of magnetic monopole, they have purposed many theories about the formation of the universe and other things. In fact, the most popular theory of this time, i.e. the string theory, is totally based on the existence of magnetic monopole. If magnetic monopole do exists, then the total shape of the theories in the physics will be completely different. A whole new physics world would be written based on the string theories.
    Generally, it is thought that if there are two electric mono poles i.e electron and proton that can exists independently, then there should also be the existence of the magnetic pole as electricity and magnetism are very closely related . The first scientist to purpose the concept of magnetic monopoles is Paul Dirac in 1931 . Dirac showed in his paper that for magnetic monopoles to exists all the electric charge in the universe should be quantized . All the electric charges in the world are quantized so it can be inferred (but not proved) that magnetic monopoles may exists. Pierre Cuire also pointed out the existence of magnetic monopoles in 1834. Ever since, then many scientist are working on the concept of magnetic monopole but so far the results are not satisfying. Magnetic monopoles have so far remained one of the mysteries in physics that many physicists wonder about . They are still remained hypothetical particle of the universe.
    Many scientist at LHC “Large Hadron Collider” are currently working on the experiments to find out the magnetic monopoles but so far no concrete results has been published. According to James Pinfold, a particle physicists at LHC, they are conducting experiment at LHC to find out the existence of the magnetic monopoles by 2011. But so far there are no results published. According to him, if these magnetic monopoles are real, they can be used to manufacture materials tough enough to withstand nuclear explosions. They can change the whole shape of the theories that has been thought to be true for so long.
    Nevertheless, LHC is currently working on the project to find the mysteries of the formation of the universe and also investigating and experimenting to find the monopoles and their mysterious. Let’s hope that these mysterious particles someday will become the part of our understanding and we would be able to find the engineering particles and mysteries of the universe.

  53. physgeeks says:



    Watch these videos and see what gravity train really means:-
    Who doesn’t want to travel at high speed and reach long distances in just a few minutes, spending couple of bucks? The world is gaining speed and people want to move quickly. They want to travel long distance in less time and money. The answer to this question is gravity train. Gravity train uses gravity of the earth to gain the speed and to stop at the station as well. So no external energy at all.
    The concept of gravity train is awesome. According to the physicists, the time that takes to travel across the world is about 42 minutes and some seconds. Anywhere you travel it takes only 42 minutes. So if you are in Paris and want to travel to New York for lunch, it is no longer a dream. All around the world in 42 minutes.
    The idea behind the gravity train is to use gravity to construct a tunnel right through the earth centre and use it to travel another place. In this process, the train uses the gravity on one surface of the earth to gain the speed and use the gravity on the other side of the earth to stop the train. So no external energy used at all. This train even saves millions of dollar that is spent on fossil fuels and other type of energy. This saves both money , energy and time. But there are some problems to convert this dream into reality.
    First of all the train, in order to gain such high speed there should air friction in the tunnel. So the air in the tunnel should be pumped out and made vacuum in order to get the high speed that is necessary . the other problem is the incredibly high temperature and pressure at the centre of the earth. So it is necessary to find the solution to these problems to turn the dream of travelling the world in just 42 minutes .
    The first problem can be solved easily but the second problem is kind of hard to solve. Now physicist are working to solve the problem of high pressure and temperature and the centre of the earth. They are saying that the time that is need to travel from one end to another end of the world is constant even if you constructed the tunnel at certain angle from the centre of the earth. But it is very hard to dig very deep into the earth . So the idea of gravity train is fascinating but it is little hard to do it. There is still some possibility that the future technology can solve this problem and make this dream a reality.

  54. physgeeks says:


    this is also a video about gravity train

  55. Dilip Kharel says:

    In general, viscosity is defined as the property of materials which is related to the ease with which they flow. For E.g. Molasses has greater viscosity than water, as water flows with greater ease.

    Quantitatively, the viscosity can be observed by considering a liquid (say water) enclosed between two plates (say P1 and P2). We suppose ‘h’ as the distance between two plates and ‘A’ as the area of contact between the plates and the liquid. If the top plate P1 is pulled with a velocity ‘v’, it is found that the liquid next to it moves along with the velocity ‘v’ and the liquid next to the bottom plate does not move.
    However, the liquid in between bottom and upper plate moves with velocity that varies between 0 and ‘v’.

    In above case, as the liquid flows, its molecules slide over each other since the velocities of different parts of liquid are different. Hence, the amount of effort that must be exerted to cause the flow will depend on the ‘friction’ between the moving layers of liquid.

    The viscosity of liquid here is determined by various things like shape, size, flexibility, forces of attraction.
    Force ‘F’ that must be exerted to move to plate P1 at velocity ‘v’ is calculated by,
    F= (η.A.v.)/h ………… where, ‘η’ is a proportionality constant.
    This force is known as Viscosity of liquid between the plates. The unit of viscosity is given as:
    η= (F.h)/(A.v) = (Newton). (sec)/(m2)

    The viscosity of liquid, on the other hand can be determined by knowing the time of flow of liquid. If ‘t’ is the time of flow, ‘d’ is the density, viscosity is given by:
    η= d. β.t ………. where, β is proportionality constant.

    In the above video, we can see that the two liquid flow with different velocity and different ease which shows that the viscosity of two liquids are different which cause the velocity to differ.

  56. Apsana Shrestha says:

    asteroidsbelt.blogspot.com and earthsgravity.blogspot.com …this is something that I prepared

  57. Brandon Landry says:

    Here is a picture of the Catapult I built.
    Catapult

  58. Brandon Landry says:

    Here is a poster I made about the trajectory of a projectile at different angles. It may be a little hard to read, but it will be posted in Physics class for those of you who would like to check it out.
    trajectory

  59. Hey this is my blog post for first two things to do.
    W# 0477044
    http://physics203.blogspot.com/

  60. hi.
    I talked about the physics that is involved in the game Angry Birds. How the angles and the amount that the sling shot is pulled back controls the direction the birds go. I also talked about how the different birds have different moves with one being able to divide into three, one being able to get its self a speed boost, and another one being a bomb.

  61. Robert says:

    hi,
    here is a video I found that i thought was pretty cool and really easy to do too.Tell me what you think about it!


    and if that don’t work try

  62. Brandon Landry says:

    Here is a picture of my potato cannon I made for Physics class.

  63. Brandon Landry says:

    Here is a note confirming that I did a presentation at Live Oak High School for Dr. Drake’s physics class on time travel.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: