Results 1 to 2 of 2

Math Help - Parachute problem

  1. #1
    Blankman013
    Guest

    Parachute problem

    Ok, i'm out of ideas so i figure ill give this a shot.

    General equation of a parabola is x(y)=ay^2+by+c, i need x(0)=10 and x(5)=0.
    So C must equal 10, and b=-2-5a. So the equation is now x(y)=ay^2-(2+5a)y+10.

    Now, from here i must somehow derive the differential equation
    (d^2y/dt^2)+(g/(1+(2ay-(2+5a))^2))=0 with y(0)=5 and y'(0)=0.

    g=10m/s^2

    I know the denominator is the same as 1+(x'^2), but apparently i have no idea how to derive differential equations. So thank you for any help!! I have more information on the problem but i'm not sure what else would be needed for the derivation.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by Blankman013 View Post
    Ok, i'm out of ideas so i figure ill give this a shot.

    General equation of a parabola is x(y)=ay^2+by+c, i need x(0)=10 and x(5)=0.
    So C must equal 10, and b=-2-5a. So the equation is now x(y)=ay^2-(2+5a)y+10.

    Now, from here i must somehow derive the differential equation
    (d^2y/dt^2)+(g/(1+(2ay-(2+5a))^2))=0 with y(0)=5 and y'(0)=0.

    g=10m/s^2

    I know the denominator is the same as 1+(x'^2), but apparently i have no idea how to derive differential equations. So thank you for any help!! I have more information on the problem but i'm not sure what else would be needed for the derivation.
    You know, it'd be best to give the entire question ....

    You start by talking about x = x(y). Then you start talking about a DE that clearly uses y = y(t). Then you mention x' implying there's a function x = x(t) somewhere ......

    If you gave a boundary condition for your DE, why not use it to get further info about the parameters (a dn b) in whatever function is relevant?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. The Parachute Problem
    Posted in the Advanced Applied Math Forum
    Replies: 2
    Last Post: February 25th 2008, 11:02 AM

/mathhelpforum @mathhelpforum