Why Am I Getting the Wrong Answer in My 2D Motion Projectile Problem?

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SUMMARY

The discussion centers on solving a 2D projectile motion problem involving a projectile launched from an incline at an angle of 39° with a launch speed of 10.0 m/s and a maximum height of 2.51 m. The participant struggles to determine the launch angle (q) and the angle of impact (a) with the incline. Key equations mentioned include basic motion equations, specifically Vf = Vi + A(D)T and Vf^2 = Vi^2 + 2A(D)X. The participant expresses confusion over the calculations and seeks clarification on the correct application of these equations.

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Crazystuntsdude
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Yeah, I pretty much spent 5 hours today trying to figure this question out, yet for some reason I keep getting the wrong answer. I told my friends I'd do it and explain it to them, but I still can't do it right. Can some one please show me the steps using only the letters, not just numbers. Thanx.

A projectile is launched into the air from the top of an incline that makes an angle f =39° with the horizontal as show in the diagram below. The launch speed, v, is known to be 10.0 m/s but the launch angle, q, is unknown. However, the maximum height above the launch level that the projectile reaches is known to be h = 2.51 m. The trajectory is a perfectly parabolic. What is the angle, a (in degrees), with which the projectile strikes the incline (measured relative to the incline as shown)? Use g = 9.80 m/s2.
http://koso.champlaincollege.qc.ca/moodle/file.php/85/q5_4ProjectileOnIncline.png
(I don't know if the picture works, but give it a shot)

Homework Equations



Basic Motion Equations
Vf = Vi + A(D)T
(D)X = Vi(D)T + (A(D)T^2)/2
Vf^2 = Vi^2 + 2A(D)X
(D) is Delta
I know Calculus, but my friends don't yet.

(I would right down one of my attempt, but it would take way too long!)
I understand how you're supposed to do it(break it up horizontally and vertically) and whatever else(ex: hor. vel. doesn't change, but vert. does due to gravity), but for some reason all the things I tried never gave me the right answer. I filled nearly five pages of stuff!
Basically, I separated the problem into four points each with their x and y values(position, velocity, acceleration) and the change in time at each one. Using the 3 equations I'm able to find all the other data, but for some reason I keep messing up no matter what way I do it. I'm certain that q = arcsin(((root)2AH)/10), but I mess u psomewhere along the line. So yeah, any help would be great.
 
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I did this quickly, so you should double check, but I think your equation is close to correct but not quite. Should it be divided by 100 instead of 10? I think you originally had (10sinq)^2, so don't you have to square the 10 as well as the sinq? (Remeber, I could be wrong).
 

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