(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A gun fires a round that goes 122 km in 170 seconds before impacting the ground. Ignore air resistance and the curvature of the earth. Find the muzzle velocity and angle.

2. Relevant equations

Vx = Vi(cos(theta)) Yx = Vi(sin(theta)) t= (-2Vy/-9.8) and D=(Vi^{2}(sin(2theta)))/-9.8

3. The attempt at a solution

I found the correct muzzle velocity. Use distance 122*1000 then divide by time. This is horizontal velocity 717.647. Then use the third equation to find vertical. 170 = -2Vy/9.8.

Then use pythagorean to find final vector: 1099.502752

Now for the angle I used the fourth equation.

122000 = 1099.502752^{2}(sin(2theta))/9.8

.9889931081 = sin(2theta)

40.74559192 degrees I guess this answer is wrong. I know the muzzle velocity is correct but according to the teacher it the angle is incorrect. Are my equations flawed or did I mess up?

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# Homework Help: Determining angle from initial velocity and distance

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