Anyone good at maths?

[FlavaDave]

I've spent the past week or so trying to figure this out (see link)



It's a graph that plots the parabola of a projectile, affected by gravity and drag. You'd set this by inputting only two variables: Initial velocity and a landing point.

Once set, I'd like to input x values and read out the y value.

It's proving quite tricky. Anyone have any ideas?

It's not for any commercial gain by the way, just an interesting side project... :-)

thanks

[FlavaDave]

Haha - good at Man Maths. We can all do that...!

Yeah probably not what people are expecting when they click through.

See what happens

[FlavaDave]

Zad said:

Rather than producing some fancy calculus derived polynomial, I would iterate it. Start with a fixed mass, velocity and direction. Resolve the X and Y vectors. Add a fixed gravity (9.81m/s/s) to each iteration of the -Y speed scalar. Subtract drag from each component speed (proportional to the square of the component speed). Update the position for each component from the x&Y speed * time interval. Iterate through it at, say, 1 millisecond intervals until Y<=0 or whatever termination you choose.

I think I understand what you're saying. If so it's a good idea to do ONE graph, but I need the formula so I can run it like a single function calculator for other inputs of Vo and X2.

[FlavaDave]

TheEnd said:

What is X and Y supposed to be in those pictures?

Distance and height in meters

[FlavaDave]

PugwasHDJ80 said:

Is the parabola a "normal" curve

if so then you can use pretty basic maths (UVAST)

No it depletes with "drag" and "gravity"

[FlavaDave]

ewenm said:

MiseryStreak said:

The height y of the projectile at distance x is given by



g: the gravitational acceleration—usually taken to be 9.81 m/s2 near the Earth's surface
θ: the angle at which the projectile is launched
v: the velocity at which the projectile is launched
y0: the initial height of the projectile
d: the total horizontal distance traveled by the projectile


Everything you need is in here:
http://en.wikipedia.org/wiki/Trajectory_of_a_proje...

If you ignore drag. The more involved maths at the bottom of the Wiki link include drag and shows how much that complicates matters!

Yes, if you ignore drag AND know the angle of elevation of the muzzle.

Anyway. We've worked it out over the weekend. Thanks for all your input. :-)

[FlavaDave]

No you can plot it without the angle. We've only just figured that out.