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

1. Feb 20, 2010

### plutonyum94

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

Cheers
Tony

EDIT:

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.

EDIT2:
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)
3

^^ thats divided by 3, btw.

ok, so is THIS is viable formula?

Last edited: Feb 20, 2010
2. Feb 21, 2010

### ideasrule

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

http://en.wikipedia.org/wiki/Magnus_effect

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