OT: Looking for a good physics site

[narf poit chez BOOM]

@Dogscoff: That would generate a pretty good intercept, but it wouldn't be perfect. To get a perfect intercept, you also have to calculate how far the target moves while the enemy is moving to where it will be then. Thanks for the idea, though.

There was distance. In fact, I'm pretty sure it was the position equation, now that I think about it. We never plugged it into the zeros-solving quadratic equation, hence no 4ac.

By 'distance' I meant we didn't take into account position. That wasn't worded well.

+/- is from the quadratic equation. There are two zeros (values of x where the curve intercepts the x axis and y is zero) in the solution to every quadratic equation. The handy cheat sheet formula compacts them into the same function, which varies only by making one version a + and the other a - where that +/- symbol goes.

So I should make two formulas, one with a '+' there and the other with a '-' there and if one returns a zero, I use the other?

The thing about the position function is that it assumes constant acceleration of both parties. It is calculating how much time passes until the objects intercept. From this, you can plot out where they intercept and get the necessary angle of motion. Remember that you had to do this every so often to find a new intercept heading, based on changes to the acceleration vectors of both objects.
I did get that.

This is what I have currently.

...Erm, does that formula give the distance that will be covered or the time to cover it?

[Fyron]

By 'distance' I meant we didn't take into account position. That wasn't worded well.

Yes we did; the very definition of intercepting a target object is when the positions are equal. We have two position equations, with two unknowns (time and position). Since we know the positions must be equal, we can simply substitute one of the equations for the S value (position) in the other equation, thus eliminating it.

So I should make two formulas, one with a '+' there and the other with a '-' there and if one returns a zero, I use the other?

No... both will return zeros of the quadratic function (aka x-intercepts). I wasn't talking about the integer value 0. A negative zero/intercept is thrown out, as per previous post.