Calculating Projectile Distance: Seeking Assistance

[naes213]

As part of a local competition, i have to calculate the distance that a projectile launched at an angle from a certain height above the ground will travel. a friend and i have attempted to shorten the three necessary steps (ignoring air resistance) into a single step.
v=rad(2gh), Dx=Vx*t, Dy=.5*a*t^2
However being at our level of experience the algebra gets a bit hairy and doesn't seem to quite work out. Any help would be greatly appreciated. (also i am not certain that i have been clear in presenting my dilemma, so i will try to clarify if necessary since I am not good at explaining things in words)


Thanks again!

 

[Hootenanny]

Do the rules of this competition allow you to receive external assistance?

 

[rcgldr]

You left out the initial velocity of the projectile when it is launched. Also, are you assuming a flat Earth (not having to worry about sub-orbital paths (ellipses as opposed to parabolas), or the strength of gravity being less at higher altitudes)?

 

[naes213]

Do the rules of this competition allow you to receive external assistance?
Yes. Its not a very serious competition, and this problem has become more of a quest than help with the competition. We can solve it with a different method, but are curious as to how this would work.

You left out the initial velocity of the projectile when it is launched. Also, are you assuming a flat Earth (not having to worry about sub-orbital paths (ellipses as opposed to parabolas), or the strength of gravity being less at higher altitudes)?
Since its not a really serious competition and the fact that it is mainly high school students we do not need to take the variability of the strength of gravity or anything else really into account. We assume as simplistic and ideal a world as is possible.
Thanks for the replies