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Homework Help: Need help with rocket math problem

  1. Aug 2, 2010 #1
    1. The problem statement, all variables and given/known data
    A rocket is fired upward from earth with initial velocity v measured in m/s. Then maximum height in m is reached by the rocket is given by the function h(v)=Rv^2/2gR-v^2
    Radius is 6.4(10^6)m and acceleration due to gravity g is 9.8m/s^2 (R and g are constants and v is the independent variable. Graph the function denoting all intercepts, asymptotes, and other points of interest.


    2. Relevant equations



    3. The attempt at a solution I used the escape velocity concept. I then plugged in the numbers given into the function. h(v)=6.4(10^6)(11100)^2/2(9.8)^2(6.4)(10^6)-(11100)^2
    Im not sure if this is correct and how to graph with the correct axes.
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Aug 2, 2010 #2

    eumyang

    User Avatar
    Homework Helper

    Your equation is very hard to read. Either use some more grouping symbols or retype in LaTeX.

    Your equation could be read like this:
    [tex]h(v)=\frac{Rv^2}{2gR} - v^2[/tex]

    or this:
    [tex]h(v)=Rv^{2/2gR} - v^2[/tex]

    or this:
    [tex]h(v)=\frac{Rv^2}{2gR-v^2}[/tex]

    and so on.


    69
     
  4. Aug 2, 2010 #3
    the last equation shown is what I meant...sorry
     
  5. Aug 3, 2010 #4
    so where's the problems in graphing the equation?
    u have the equation, h(v), take the x-axiz for v and y-axis, for h
    But the graph will be a little difficult to sketch with ur hand, so u may take help of some graphing software

    i couldnt get why u needed to use escape velocity concept or something. wat i see the problem, its just a single variable equation that is to be graphed.
    plz clarify if i missd or misundstood something.
     
  6. Aug 3, 2010 #5
    I used the escape velocity because my teacher gave us a hint using that and told me to look that up. So am I right in plugging in the numbers into the function the way i did above? Yeah I am using grapher to graph the equation. I just want to make sure I plug the correct function into the graph.
     
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