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Homework Help: Help Needed!

  1. Oct 3, 2005 #1
    I have no idea why I'm taking physics when I really have no wish to take another math/science class, but I am. The only problem is I have no idea what I'm doing, and we're just learning very basic physics right now.

    Ok, so now for my problem on motion (which is basically just a need for formulas and little direction):
    A. How do you determine the average velocity of an object?
    B. How would you then write a mathematical equation to describe the motion?

    I know what I've asked is really simple, but I just need a little direction. Leaning how to find A. and B. will also help with other problems I have. My teacher does not teach physics in a way I can understand, so any help I can get will be greatly appreciated.
  2. jcsd
  3. Oct 3, 2005 #2
    average velocity = distance/time
  4. Oct 3, 2005 #3
    to be more specific to my reply:

    average velocity= your final distance - your initial distance all divided by your final time and your starting time... if youre given those pieces of information :)
  5. Oct 3, 2005 #4
    Bassically, with these types of easy questions, try to relate things to your experiences. So if you want to know the average velocity, think to yourself what velocity is, obviously it's just how fast you went a certain distance. So now try to apply it to a situation, like if you were to travel from where you live to the store, and wanted to know what your average speed was, what would you do? First, you know that velocity or speed is just distance divided by time(miles per hour for example). So you could figure out how far the store is by looking at your odometer in your car and driving there. To figure out time, you would just see how long it took you. Now if you divided your total distance, by total time, you would have your average velocity. So to get an equation for this, think of how you got your answer or think of common units, so in this case you divided distance by time(like the unit miles per hour), so that is your equation right there.

    I know that I oversimplified things WAY too much, but this is a way to solve any simple question, just get used to thinking in this way.

    EDIT: If you truly want the vectory quantity of velocity(I'm not sure if in your physics class you distinguish between velocity and speed, if so, than this is valid for your class) then you would have to find the straight line distance from where you start to your destination. Like the path you would take with a helicopter instead of a car.
    Last edited: Oct 3, 2005
  6. Oct 3, 2005 #5


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    Homework Helper

    Average velocity is a vector. You get it by taking your displacement - that's the straight-line distance from your origin to where you are, including the direction - and dividing by time. As for an equation describing it's motion - well, assuming it's at constant velocity, that would just be

    s = vt

    (with the little "vector" signs over the s and the v.) s is the displacement, v is the velocity - but you probably already knew that.
  7. Oct 3, 2005 #6
    :smile: Thanks everyone!! It really helped.

    FYI, expect to see me here alot. Hope you don't get tired of me :tongue:
  8. Oct 3, 2005 #7


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    Homework Helper

    Don't worry, hon. If we were the type to get tired of answering questions, we wouldn't post here. :smile:
  9. Oct 3, 2005 #8


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    Gold Member

    Welcome to PF, Lloydsgurl. This is one of the best learning resources available anywhere, and definitely the best on the net. Stick around, and you'll end up learning stuff you don't even want to know (especially in GD). :biggrin:
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