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Homework Help: Anybody know the formula for the Magnus Effect?

  1. Feb 20, 2010 #1
    I realise I may way out of my depth here....
    but i thought i'd jump in anyway.

    so thats the question...is there a specific formula?

    feel free to call me an idiot if i've got this all wrong :P



    sorry, i forgot a bit of background....
    so i'm doing a physics experiment revolving around modelling true golf ball trajectories. the magnus effect plays a pretty large role, and in my hpothesis, i'd like to create a formula factoring it in.

    ok, so i THINK i've found a formula...
    i dont know how everyone else gets the cool symbols, so im just going to use regular letters. sorry if its confusing...

    Fm = 2pi(p)(w)(vx)(h r^2)

    where p = density at 25 degrees C, w = angular velocity, vx - horizontal velocity and h r^2 = height of cylinder multiplied by the radius squared.

    this formula is for a cylinder.
    i've rearranged it:
    Fm = 2(p)(w)(vx)(pi r^2 h)

    now, as far as i can remember, pir^2h is the formula for the volume of a cylinder...
    as im looking at golf, i've taken out that formula and replaced it with the formula for the volume of a sphere:

    Fm = 2(p)(w)(vx)(4/3pi r^3)

    which eventually, returns the pi to the front:

    Fm = 8pi(p)(w)(vx)(r^3)

    ^^ thats divided by 3, btw.

    ok, so is THIS is viable formula?
    Last edited: Feb 20, 2010
  2. jcsd
  3. Feb 21, 2010 #2


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    Homework Helper

    I don't know where that formula came from, but have you checked Wikipedia's article on the magnus effect? See:


    There's a formula, along with typical values of the lift coefficient.
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