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Homework Help: How do u solve this

  1. Jan 9, 2008 #1
    i am not sure if its the right place to post this thread

    m * g * h = 0.5 * m * v^2

    m= 20*10^-3
    g= 9.81
    h= 11

    20*10^-3 * 9.81 * 11 = 0.5 * 20*10^-3 * ???

    i have to solve V^2

    the answer is 15m/s...

    thanks a lot
  2. jcsd
  3. Jan 9, 2008 #2
    This'll probably be moved pretty quick, but for reference this is mathematically an algebra level problem, and obviously an intro physics problem, so either intro physics or whatever the lower math one is, certainly not calculus and beyond though

    With that said: Do you know ANY algebra? If not, this isn't the place to learn it and you might wanna mention that to your teacher 'cuz you'll fail a high school physics course without at least a basic knowledge of it. I ask 'cuz you didn't show any work besides just plugging in the numbers, so I can only assume you don't know where to start

    If you're just rusty or perhaps overthinking it painfully, just remember it's basic algebra. Before you even plug in the numbers you can divide both sides by m, making them cancel and leaving g*h=.5*v^2

    Do you have any idea what to do after that?
  4. Jan 9, 2008 #3

    Do you have any idea what to do after that?

    no not at all so?
    yeah man i dont know all that so i asked it if someone can explain how it works
    if you do not want to help plz leave it thanks
  5. Jan 9, 2008 #4
    Helping's peachy but we're not gonna do it for you outright

    The goal of this, and most similar math problems, is to get the variable, the thing you wanna find, by itself on one side. What can you divide both sides by to get the v^2 by itself? Once you have v^2=stuff you can do something else to both sides to get just v
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