I'm having some difficulty with a projectiles question. "A projectile is fired with an initial speed of 26.0 m/s at an angle of 40.0 degrees above the horizontal. The object hits the ground 8.00 s later." The first part of the question is: "How much higher or lower is the launch point relative to the point where the projectile hits the ground? Express a launch point that is lower than the point where the projectile hits the ground as a negative number." Which I already found out using y=(viy)(t)-(1/2)(g)(t^2) Substituting the given numbers, I get -180 m, which would be the case if the landing point was below the launch point. Since the question wants a launch point lower than the landing point, the answer is 180 m. The second part, where I'm having trouble: "To what maximum height above the launch point does the projectile rise?" What I have, x=(26)(cos(40))(t) y=(26)(sin(40))(t)-(1/2)(g)(t^2) I can't substitute 180 m or 8 s because those numbers apply to the landing point, and I'm looking for ymax so I end up with three unknowns in two equations, which I cannot solve. I don't know how to set this up so that I can solve it. Thanks for any help!