Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

If i know velocity, then i know acceleration right?

  1. Jan 11, 2005 #1
    For velocity at a certain particle in a simple harmonic oscillation is the following:

    v= w (anguluar frequency) times the squareroot of A^2-x^2

    but if i wanted to find the acceleration at a certain particle in a simple harmonic oscillation, i can somehow derive a formula from the above equation right? But how would u derive it?

    I know that that V= dx/dt ..and a= (d^2)x/dt^2

    ugh, i forgot my calculus, anyone clear it up for me?

    thanks
     
  2. jcsd
  3. Jan 11, 2005 #2
    for simple hamonic motion
    [tex] x = A \sin{( wt-\theta)} [/tex]
    I have no idea what is your equation looks like

    v= w (anguluar frequency) times the squareroot of A^2-x^2 :confused:

    put it in Latex pls.....
     
  4. Jan 11, 2005 #3

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    The equations for linear harmonic oscillator are something like that
    [tex] x(t)=A\sin(\omega t+\phi)[/tex]
    [tex] v_{x}(t)=A\omega\cos(\omega t+\phi) [/tex]
    [tex] a_{x}(t)=-A\omega^{2}\sin(\omega t+\phi) [/tex]

    Then decide what are the initial conditions.And u can determine the 2 unknowns;

    Daniel.
     
  5. Jan 11, 2005 #4
    [tex] v= w \sqrt{A^2-x^2} [/tex] is that what you trying to say???
     
  6. Jan 11, 2005 #5
    OKAY, i dunno where did you get this equation.... this is right but ppl usually don't write it this way, if you wanna find a(t) from your equation, substitude v=dx/dt, you have
    [tex] dt=dx/ (w \sqrt{A^2-x^2}) [/tex]
    integrate both side and you will have[tex] x(t) = Asin(wt+\theta)[/tex]
    after you have x(t), everything should be easy
     
  7. Jan 11, 2005 #6
    yes,

    [tex] v= w \sqrt{A^2-x^2} [/tex]

    is what i am trying to say, so how can u derive a formula from the above equation for acceleration? that is my question
     
  8. Jan 11, 2005 #7
    did i just tell you.. do the integral and find x(t)
    after you have x(t), v(t)= dx/dt, a(t) = dv/dt
     
  9. Jan 11, 2005 #8

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    The formula is deduced from applying the law of energy conservation.Once u integrate this ODE (using the method prescribed above),you need to diff.2 times wrt to time to find the acceleration.

    Daniel.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?